If I do away with the active bass/treble control " the two pots on it", and make it flat on the tone, It would be totally digital control. Then you could go with membrane keys, for volume, and balance. Heck, then you could pot it into a block.
I still have some more work, but should have it going next week.
Cost wise, the pc board was about $ 15.00 for board + chemicals, all the other parts about $ 20.00
Plus 2 weeks design time.
I must admit, this has been fun to me. After complete, I want to get a broken Jeep radio, to build it into.