diff --git a/core/lib/Drupal/Core/Config/Entity/Display.php b/core/lib/Drupal/Core/Config/Entity/Display.php
index 09c1221..5b65111 100644
--- a/core/lib/Drupal/Core/Config/Entity/Display.php
+++ b/core/lib/Drupal/Core/Config/Entity/Display.php
@@ -13,7 +13,7 @@
  * Configuration encapsulator that provides all the data needed by block-driven
  * controllers to render a page.
  */
-class Display extends ConfigEntityBase {
+class Display extends ConfigEntityBase implements DisplayInterface {
 
   /**
    * The ID (config name) identifying a specific display object.
@@ -40,7 +40,7 @@ class Display extends ConfigEntityBase {
   /**
    * The layout plugin instance being used to serve this page.
    *
-   * @var Drupal\layout\Plugin\LayoutInterface
+   * @var \Drupal\layout\Plugin\LayoutInterface
    */
   protected $layoutPlugin;
 
@@ -119,70 +119,113 @@ class Display extends ConfigEntityBase {
    */
   public $blockConfig = array();
 
+  protected $blocksInRegions;
+
   public function __construct(array $values, $entity_type) {
     $this->layout = $values['layout'];
     // @todo oh so much, but really, blocks for now.
     parent::__construct($values, 'display');
   }
 
-  /**
-   * Sets the controller that should be used to serve the main page content.
-   *
-   * "Main page content" is analogous to the callback specified in
-   * 'page callback' in Drupal 6 and 7. In a blocks-driven world, such direct
-   * callbacks run a bit against the grain. However, the simplicity of
-   * implementing and understanding it is so beneficial to developer experience
-   * that we provide this 'main' content option, which simulates the old
-   * behavior by injecting a virtualized 'main' block that passes through
-   * to a specified callback.
-   *
-   * We normalize the main content block here in the configuration object so
-   * that various controllers consuming the display need not repeatedly
-   * implement this special handling for the main callback.
-   *
-   * @param Callable $callback
-   *   Any form of callable. @todo PHP 5.4 allows type hinting as Callable.
-   * @param array $args
-   *   An array of arguments to pass to the callable.
-   */
   public function setMainContent($callback, array $args = array()) {
     // @todo need to wrap the callback up in a passthru block
     // @todo consider throwing an exception if this display instance doesn't appear to support main content
   }
 
+  public function getAllBlockInfo() {
+    return $this->blockConfig;
+  }
+
+  public function getSortedBlocksByRegion($region = '') {
+    if ($this->blocksInRegions === NULL) {
+      $this->sortBlocks();
+    }
+
+    if (!isset($this->blocksInRegions[$region])) {
+      throw new \Exception(sprintf("Region %region does not exist in layout %layout", array('%region' => $region, '%layout' => $this->getLayoutPluginInstance()->name)), E_RECOVERABLE_ERROR);
+    }
+
+    return $this->blocksInRegions[$region];
+  }
+
+  public function getAllSortedBlocks() {
+    if ($this->blocksInRegions === NULL) {
+      $this->sortBlocks();
+    }
+
+    return $this->blocksInRegions;
+  }
 
   /**
-   * Returns the config info about all blocks on this display.
+   * Transform the stored blockConfig into a sorted, region-oriented array.
+   */
+  protected function sortBlocks() {
+    $layout_instance = $this->getLayoutPluginInstance();
+    if ($this->layout !== $layout_instance->name) {
+      $block_config = $this->remapBlocksToLayout($layout_instance);
+    }
+    else {
+      $block_config = $this->blockConfig;
+    }
+
+    $this->blocksInRegions = array_fill_keys(array_keys($layout_instance->getRegions()), array());
+    foreach ($block_config as $config_name => $info) {
+      $this->blocksInRegions[$info['weight']] = $config_name;
+    }
+
+    foreach ($this->blocksInRegions as &$region) {
+      krsort($region);
+    }
+  }
+
+  /**
+   * Remap the the saved blockConfig to work in a different layout.
    *
-   * There are two levels of configuration that are being captured here: the
-   * configuration for the block itself (i.e., config generated by a user saving
-   * the block's edit form), and configuration for how the particular block
-   * instance behaves in *this* display. The former is typically its own config
-   * object, and only a reference to that config key is stored directly on this
-   * object. The most important examples of the latter are the region in which
-   * the block is placed, and its weighting within the region.
+   * @todo this logic is a good default, but should be alterable.
    *
-   * @todo we need to explore a *lot* more just how freestanding we make blocks.
+   * @param \Drupal\layout\Plugin\LayoutInterface $layout
    *
    * @return array
-   *   An array of block info, keyed on each block's config name.
-   *
-   * @todo implement batch-loading logic to try to minimize discrete queries.
+   *   An array containing block configuration info, per the blockConfig property.
    */
-  public function getAllBlockInfo() {
+  protected function remapBlocksToLayout(LayoutInterface $layout) {
+    $roles = array();
 
+    $layout_regions = $layout->getRegions();
+    $layout_regions_indexed = array_keys($layout_regions);
+    foreach ($layout_regions as $name => $info) {
+      $roles[$info['role']][] = $name;
+    }
+
+    $remapped_config = array();
+    foreach ($this->blockConfig as $name => $info) {
+      // First, if there's a direct region name match, use that.
+      if (!empty($layout_regions[$info['region']])) {
+        // No need to do anything.
+      }
+      // Then, try to remap using region roles.
+      else if (!empty($roles[$info['region-role']])) {
+        $info['region'] = $roles[$info['region-role']];
+      }
+      // Finally, fall back to dumping everything in the layout's first region.
+      else {
+        $info['region'] = reset($layout_regions_indexed);
+      }
+
+      $remapped_config[$name] = $info;
+    }
+
+    return $remapped_config;
   }
 
-  /**
-   * Returns the layout plugin instance to be used with this display.
-   *
-   * @return Drupal\layout\Plugin\LayoutInterface
-   */
   public function getLayoutPluginInstance() {
     if ($this->layoutPlugin === NULL) {
-      // @todo if we're doing any magic resolution/hotswapping of layouts, this
-      // is a place it could happen.
+      if (empty($this->layout)) {
+        throw new \Exception(sprintf('Display with id %id had no layout plugin attached.', array('%id' => $this->id)), E_RECOVERABLE_ERROR);
+      }
+
       $this->layoutPlugin = layout_manager()->createInstance($this->layout);
+      // @todo add handling for remapping if the layout could not be found
     }
 
     return $this->layoutPlugin;
diff --git a/core/lib/Drupal/Core/Config/Entity/DisplayInterface.php b/core/lib/Drupal/Core/Config/Entity/DisplayInterface.php
new file mode 100644
index 0000000..f114c1b
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/Entity/DisplayInterface.php
@@ -0,0 +1,84 @@
+<?php
+/**
+ * @file
+ * Definition of Drupal\Core\Config\Entity\DisplayInterface
+ */
+interface DisplayInterface {
+
+  /**
+   * Introspects the contained config to determine whether or not this Display
+   * supports the 'main content' passthrough.
+   *
+   * @return bool
+   */
+  public function hasMainContent();
+
+  /**
+   * Sets the controller that should be used to serve the main page content.
+   *
+   * "Main page content" is analogous to the callback specified in
+   * 'page callback' in Drupal 6 and 7. In a blocks-driven world, such direct
+   * callbacks run a bit against the grain. However, the simplicity of
+   * implementing and understanding it is so beneficial to developer experience
+   * that we provide this 'main' content option, which simulates the old
+   * behavior by injecting a virtualized 'main' block that passes through
+   * to a specified callback.
+   *
+   * We normalize the main content block here in the configuration object so
+   * that various controllers consuming the display need not repeatedly
+   * implement this special handling for the main callback.
+   *
+   * @todo this is fairly specific to pages - maybe not best for the interface
+   *
+   * @param Callable $callback
+   *   Any form of callable.
+   * @param array $args
+   *   An array of arguments to pass to the callable.
+   */
+  public function setMainContent($callback, array $args = array());
+
+  /**
+   * Returns an indexed array of block config names, sorted by the order in
+   * which they should appear in the region.
+   *    *
+   * @param string $region
+   *   The region from which to return the set of blocks.
+   *
+   * @return array
+   */
+  public function getSortedBlocksByRegion($region = '');
+
+  /**
+   * Returns an array of arrays, keyed by region name and containing the
+   * same data as that which is returned by
+   * @see DisplayInterface::getSortedBlocksByRegion().
+   *
+   * @return mixed
+   */
+  public function getAllSortedBlocks();
+
+  /**
+   * Returns the config info about all blocks on this display.
+   *
+   * There are two levels of configuration that are being captured here: the
+   * configuration for the block itself (i.e., config generated by a user saving
+   * the block's edit form), and configuration for how the particular block
+   * instance behaves in *this* display. The former is typically its own config
+   * object, and only a reference to that config key is stored directly on this
+   * object. The most important examples of the latter are the region in which
+   * the block is placed, and its weighting within the region.
+   *
+   * @todo we need to determine how freestanding block config is.
+   *
+   * @return array
+   *   An array of block info, keyed on each block's config name.
+   */
+  public function getAllBlockInfo();
+
+  /**
+   * Returns the layout plugin instance to be used with this display.
+   *
+   * @return Drupal\layout\Plugin\LayoutInterface
+   */
+  public function getLayoutPluginInstance();
+}