Ability to Select `View Mode` of Block when creating a block reference

This is Bean centric, but something like the attached patch.

Here's another version of that patch. It removes some cruft and uses a consistent method for getting available view modes.

Here's another version of that patch. Less cruft again.

All good points and we could certainly make this a separate module. I believe that the issue with using entityreference module is that sometimes the editors want to reference a Bean Block, other times they want to reference a View Block. Utilizing this patch we get Drupal closer to giving editors an MVC like experience. The blockreference field becomes a Controller that editors use to combine a Model (the Bean Block) and display it with a View (the View Mode) of their choice. If an editor wants to include a Collection View, they use the Views module as the Controller that manifest itself as a Block that contains a Collection of Models (the Filter options), the Collection View (the Style plugin chosen), and the Item View (the View mode chosen for items).

Ultimately I would like to see a workflow as follows...

1) User selects View, maybe referred to as Widget which is generated from a list of Style plugins and View modes.
2) User adds View specific configuration (ie. sort order in the case of a Table).
3) Given the type of Widget (Item View or Collection View), user is asked what Model or Models to place in the View.

That's just an idea at the moment, for now I think this patch (or separate module) could be improved by only displaying the View Mode select if a Bean is selected.