I've been having a good time with Dean's eZ80 board so far! Build's been pretty smooth, though I really suggest you heed the build notes' advice about wedding the CPU carrier's pins with the female receptacles before soldering either to their respective board. Aligning all the pins after you've soldered the female receptacles to the main board is doable, but really not the easiest way to do it.
So far, my stack's comprised of a CPU board, a SC729, and a SC721. I'm hoping to add the linear SRAM, FPGA video, and USB host before my stack's set to go up on exhibit alongside a grab bag of other RomWBW systems at VCF Midwest in september.