That looks great! Care to show how you connect the potentiometers inside? Sliding pots? Or have you thought that far yet?
There is one problem though - you mixed up the throttle and prop control shapes - the "spikes" are in prop handles, and the throttle levers usually have round knobs - and mixtures have the "gearwheel" -like knobs (like your throttle also has)
See here for an example:
http://www.airliners.net/open.file/499870/L/
But great work otherwise, looks like it will be excellent!
Best,
Tuomas