Build-it-in for yummy times..
I loved the idea behind Paul Slocums Cynthcart for the Commodore 64 so much, that I wanted to extend it to his Synthcart for the Atari 2600. If you can wire pots inside a C64 case instead of using Paddles, why not wire a couple of 12 Digit NumPads inside a 2600?
The NumPads are cheap from Jaycar, especially compared with finding Atari Video Touch Pads and the like. And I think this way looks supercool!
Structurally, its VERY solid. The Pads sit on the RF sheild inside the 4 and 6 switch models. If any of you have seen the hunk of metal inside these things you'll know how OTT that thing is!
KeyPad combinations are printed on the front for easy reference, however I might expand this to cover the full width. I would like the table from the cartridge label regarding waveform select to be more accessible too.
Perhaps an internal MIDI kit from Highly Liquid would finish this one off nicely ; )