Contextual Entity List

Reading the description of your project, it seems to me that you like challenges. :)
I'm not sure that I understood it all for the first read (especially, what use case is it for exactly), but would really like to dig deeper into it, so I checkout your code soon, and start playing with it.

For the first manual review of your code, I couldn't find any critical issues. I haven't tested your module yet, that will be the next step.
Could you please explain me why are you providing those < option > tags in JS. Don't you think that using an AJAX form would be a better idea?
My other question is, if it's necessary to use that JS provider, don't you think that using a more module specific menu callback is a good idea instead of 'bundles', eg. 'contextual-entity-list-bundles' ?
Actually I'm not using Panels for my projects, so not very familiar to it.

Otherwise, I've found some typographic mistakes in your comments.
Let me correct those, what can help your efforts:

This is a module file having register contetual plugin from this module file.
This is a module file having register contextual plugin from this module file.
$plugin takes the plugin defination.
$plugin takes the plugin definition.
Ajax-Call-back.
AJAX callback.
Context call back.
Context callback.
Context configuartion for entity type.
Context configuration for entity type.

If there is no bundle for an entity type (eg. there's no vocabularies in the system), the Bundle type selection remains the previous, (the HTTP response body is empty), and it throws the JS error:
Uncaught TypeError: Cannot read property 'length' of null
And you can not select other entities thereafter because of the above.

I suggest you to rewrite the form using an AJAX callback bound to the entity selector, replacing the whole form or the bundle selector part of it in your callback.
Here's a good explanation: http://drupal.org/node/752056

manual review:

1. Project page is not very clear, what is the use case? See http://drupal.org/node/997024
2. contextual_entity_list_menu(): why is the permission just "access content"? who should be able to retrieve data from that callback?

But otherwise looks RTBC to me. Removing review bonus tag, you can add it again if you have done another 3 reviews of other projects.

Nice work.
Excuse me to change it's status back to needs work.

I understand, that you are integrating into a CTools modal, and maybe you can not use standard AJAX techniques. (I can't confirm nor refute)
My only notice is that it doesn't seem safe enough for the first sight:

  $options = '';
  $entity_options = _contextual_entity_list_entity_options($entity);
  foreach ($entity_options as $key => $value) {
    $options .= "<option value=$key>$value</option>";
  }

Direct variable injection into strings (especially output) are avoided in drupal code. In this case I think you should better use check_plain or filter_xss_admin, like:

    $options .= '<option value="' . check_plain($key) . '">' . filter_xss_admin($value) . '</option>';

(corrected)

added sandbox link

Hi roynilanjan!
I've checked the source code on the day you committed.
I saw that you made changes you mentioned, and changed the satus back to 'reviewed & tested by the community' such as klausi had previously.
I thought everything is fine and the status 'reviewed & tested by the community' is correct.

The project page is still unclear. What is this module good for?

So imre.horjan also thinks this is RTBC, let's go ...

Thanks for your contribution, roynilanjan!

I updated your account to let you promote this to a full project and also create new projects as either a sandbox or a "full" project.

Here are some recommended readings to help with excellent maintainership:

• Dries' post on Responsible maintainers
• Best practices for creating and maintaining projects
• Maintaining a drupal.org project with Git
• Commit messages - providing history and credit
• Release naming conventions.
• Helping maintainers in the issue queues

You can find lots more contributors chatting on IRC in #drupal-contribute. So, come hang out and get involved!

Thanks, also, for your patience with the review process. Anyone is welcome to participate in the review process. Please consider reviewing other projects that are pending review. I encourage you to learn more about that process and join the group of reviewers.

Thanks to the dedicated reviewer(s) as well.