Hi,
if i can add a expasion memory together (adide+memory+cpu), for example the expasion memory CDTV of elbox.
There is a memory card by W.A.W which connects to the CDTV's Diagnostic slot called the bigram8 which lets you add up to 8MB fast ram, thats probably better than an elbox style memory card on top of an adide card.
Other than that why not get an SCSI card and connect a harddrive that way and use the elbox mem card with the 68000.