The humble TR-606, drum machine brother of the TB-303, doesn't usually get much love, but some people are obviously feeling it. eBay item #7354365370 is a 606 in a 6U rackmount, surrounded by what look like Doepfer modules. It has MIDI sync, individual outs and triggers, a rash of blue LEDs, and a wide selection of both bells and whistles, all wrapped in a slightly icky looking wooden cabinet with a brass plaque. Currently £155 with six days to go. (thanks Alex, also seen on the mighty Matrix Synth)
UPDATE: Turns out this was built by Allan Hall who has also done a similar 909 mod, and built a VCS3 from various hacked modules from Analogue Solutions.