I was mostly the money, Mark Dusko was the actual hardware guy. He has his design up on his website, though. I am sure he would have no problem if someone wanted to make another run. I have not heard from him in some time, but his atariage handle is puppetmark. I would imagine that dropcheck or one of the other folks still producing boards would be able to handle it. I think a pass-through cart would be much better, and/or a PBI device. The CS8900A is hard to source in 5 volts. Lots of people seem to think that a 'all in one' with its own TCP stack is the way to go, but unless it has a memory mapped transfer bus it won't work very well. SIO is not capable of handling it. And, as you've seen, a dedicated single purpose stack is very doable on the eight bits, especially to support UDP.