I've managed to get my hands on a IICX adapter, and have completed the pinout page. In theory, this diagram could be used to wire up an adapter between Daystar accelerators and any 68030 socket.

http://hiddenkingdom.net/temp/pinout.htm

My only remaining question is this: the card has 8 small capacitors arranged in parallel. All of them bridge +5VDC and GND. This puzzles me. Can anyone with some EE experience explain this? Why use 8 small caps rather than 1 large cap?

Now to build one and see if it works...