I love that idea. The thought of having the original radio in place and light up, and having the dials to manipulate the amp is great. Of course the devil is in the details.

My two cents. get the lights on the radio to work, and forget about the rest. wire the amp into the radio feed so they both come on together. mount a regular amp under the seat or on top of or underneath the radio in the dash along with some 5-1/4" speakers. and find one that has a USB port to plug in and charge your ipod/iphone.

You have given me a great idea. Now I am interested in finding an old radio to try this with. hmmmmmmmmmmmmmmmm.