Add ability to create custom "smart" controls (similar to iPhone Menu, button bar, etc).

I have seen a lot of people asking for the ability to create custom widgets and it looks like this has been added through image imports, etc. That is great and works for some things but what I would really like to see in addition to that is the ability to create custom "smart" widgets similar to the iPhone Menu, button bar, etc.

I call these "smart" because their aren't a single image. Instead they allow the user to customize them through settings and smart text processing. For example I really love how simple the iPhone Menu one is but still allowing all standard iPhone interface elements.

Are our company (and I guess others), we have a large set of customized widgets that allow us to reuse the same interface paradigms throughout the application. If there was some way to create "smart" controls for these is would dramatically improve our sketching abilities.

As far as form, I would build on however the ones in the system are currently specified. For example if the user could manually create an XML file in a text editor that showed options or used some command sequence / programming language to specify what to draw when the user customizes a setting or text. Even better, tie this into the mockupstogo and allow users to share their custom controls.

Anyway, that is my idea. Any thoughts?