Jens, I believe, is very wary of having his good reputation tarnished. While in theory it's a very good idea to sell bare boards without CPUs, in practice it would create reports of unreliable hardware as people use the wrong parts, and however much that's undeserved, it would damage his reputation. Hence I can see exactly why he's not doing that.
Incidentally, the ACA 1230 seems to be using a PLCC chip instead of a PGA like most accelerators. I was thinking of plonking my full '030@50 into a 1230/28 but it wouldn't fit even if I could find where the clocking is done.
