Nice UI button
Buttons And Switches(PSD) dload link: http://dribbble.com/shots/797923-Buttons-And-Switches-PSD/attachments/81063
Switch Button by Javi Perez via Dribbble
25 Beautifully Designed User Interfaces | From up North
Radialslider - Anton Kudin Had an idea of this bit of touchscreen UI. Could be a bit more useful than a knob.
Nice looking but very unsure of the constant reproduction of physical items in a digital UI
Dribbble - Switch by Ivan Kutcher