Oktagon uses ZIP-chips as found in the A3000, very hard to find and expensive.....
Some years ago I bought an empty RAM-board that would take 16 1-Megabit-chips for the 1st 2MB and 3 SIPPs (think of 8-Bit-SIMMs with pins) for another 6MB.
I bought it for a reason, I had an obsolte 386SX laying around, which had 18 of these chips :-P
Probraly your best guess, look out for real old PC-mobos populated with atleast 2MB (everything smaller won't have the right chips), and not useing any kind of SIMM.
Late 286, and early 386DX/SX are good candidates.