Rather than try and emulate the buttons and knob on the Empeg, surely a touchy interface on an iPhone/Pre/Android would work better with a iPeng or SqueezeControl style interface. It would be fun for back seat passengers to flick through your music on a phone if you had wireless in your car, or it could turn your Empeg into a serverless Squeezebox Duet at home. Album art and info could be got online and it could be a cute, fun and useful project.