Coleco Donkey Kong is working in MESS now, with the speaker volume decay implemented. I'm still interested in the circuit schematic, so someone experienced with MAME/MESS discrete audio emulation can add it.

Sean: I wouldn't risk purchasing that TI-30, maybe it's simply a homebrew power-supply?
Rik: welcome! =)
Flying Ape: external artwork is possible for Dark Tower, you could ask around on the MAMEWorld Artwork forum. Sean also made many photos that should be useful(go back a few pages where he posted them)