Do you have a clue what this will cost for us to have one?
For the parts along I think it's about $30. The most expensive thing is the ATMega with USB.
The price jumps up a lot if I can't manage to route all of the signals onto a 2 layer board and need to use 4 layers though.
Would this be pre-built, or a kit, or just a board with a CPU?
It would be pre-built I think. I have 50+ of all of the parts except the CPLD and ATMega.
Any particular reason you stopped at 6MHz?
It's what the guy had for sale. :) The Z80s cost me 580 yen + 700 yen shipping. I bid on them thinking I would never get them for that price. The same guy puts out lots of 96 QFP Z80s every so often and they usually go for ~9000yen.
Cheers,
Daniel