Price-wise, the one you linked to seems to be pretty good value. Given the number of vias, I'd be surprised if Amigakit is making more than a nominal handling fee on them.
That's not the one I was thinking of though, it looks more like a breadboard.
The board I (thought I had) heard mentioned offered the Xorro slot's i/o pins (and possibly power, etc) to a connector (eg a D-Sub) on the backplane.
@Amigakit - not sure if you have already, and I'm sure you'd have it well planned out, but if designing such a board it may be worth adding a 6-pin PCIe power header on the expansion board to be powered directly from PSU, and putting some current-limiting circuitry to the Xorro connector to prevent the possibility of shorting the PCIe power lines on the PCIex16 slot to ground (assuming that Xorro has the 12V 75W power supply lines connected as per PCIe spec).
PSUs are easier to replace than Nemos after all. 
Thats a nice idea. However that would require a board redesign and the boards are already made.
Seriously though if your going to be playing with a project board. You should be aware of the risks and dangers of shorting out voltage rails. If your unsure, its a case of check, double check and triple check.
Im sure someone will pick at what I have posted, but lets face facts.
I may be an Electronics Engineer and know about Electrics, doesnt mean I will go play with the mains Electrics in my house. I check, double check and triple check before doing anything. If Im unsure I will leave it until I know.
If we had all this tech around when I was a kid, Im sure I would playing around with the zorro board to do different stuff. Spose its a bit like the electronics lab I go as a kid, made lots of things with that including my first AM Radio.
