Add a new node type, mm_block, which allows the contents of any block to be displayed as a node. This provides an easy way to put a node on a single page without it also appearing on every other page that uses the same theme.
Instead of reusing the no_breadcrumb flag to send the meta tag asking crawlers to not index the page, create a new flag called no_index. Any pages relying upon no_breadcrumb for this will have to have the new flag checked instead. Hint: Use MM's Search feature to identify these pages.