If you've got an LCIII, have I got an adapter for you!!!! :lol:

I haven't found the IIcx Adapter, but I've got Version 1.0 of the:

Universal PowerCache Installation Manual for the Mac Color Classic, LCIII, and Performa 450

You should see all the chips on the CC Adapter! 8-o

The LCIII/P450 Adapter doesn't have any logic on it, just some resistors/assorted digital glue.