UI wheel and buttons properly termed constraint buttons. Wherever an intrinsic scale is present you can be sure constraint buttons are in the mix. Further more the circle or wheel design offers economy of design
25 Beautifully Designed User Interfaces | From up North
Viro Media Controls - Free UI Kit
GUI toolkit that actually looks like it's been designed to work well on a touchscreen. Button and sliders are tangible. Only rotating elements are incredibly large and easy to manipulate. A lot here to like.
Week 1 - Skeuomorphic Web Design - This is about a real looking UI kit. The switches, knobs, and buttons all look as if this were a real board.