If you are a app designer yourself, you may be interested in RIM's latest contest called, Stump the Devs:
How do I stump someone and who am I stumping? Provide us with a design or mock-up that you think would be difficult to be implemented using our Cascades™ UI framework. The Cascades tools development team will try to implement your submission in a flexible manner that involves no hardcoding of values and that is flexible enough to handle multiple screen resolutions and multiple form factors.
Be sure to let us know if you submit a UI design of your own to stump the devs. Even better, post a picture of your design in the comments below!