You should be able to buy kits that will get you 80% there. Then its just about packaging it up in the correct way and wiring it all together.
Radioshack should have a kit for the amp.
As for the equaliser thats a bit more tricky but something like this - http://www.quasarelectronics.com/sma...-equaliser.htm should work ok.

Personally I would take the easier route by finding something that already does what you want (car stereo, or audio seperate) and then remove the parts I want and repackage them.