The real value is probably Wayfar’s MIDINES and Paul Slocum’s Synthcart which are also included with each console. From listening to the sample of the NES it appears as though the mod is the solo instrument switch hack, seen in the Barbie NES posted earlier. Pretty useless if you are using MIDINES, but if you just need that juicy bassline from Indiana Jones and the Temple of Doom you can have it. The Atari video mod is interesting, however the real kicker is the Sega Rapid fire joystick. When used with the LightShow mode of the synth cart it triggers sounds very rapidly. Perhaps if modified to change speed the rapid fire it would be even better, Great idea, and I don’t see a reason why this joystck can’t be used with other circuit bent things to close switches for instance, very rapidly though. I am sure they are super cheap nowadays as well.
Modded Atari on eBay link
Modded Nintendo on eBay link
Sellers website: http://www.dispyz.com/bends.html
Video Link: http://www.dispyz.com/bent/ataribend3.AVI