Hi, just popped in and saw this thread. I might still have a tube of the chips needed to bring it up to 2MB. Can't recall if I got rid of those or not. Will try to take a look around later. I upgraded mine from 2MB to 8MB years ago, since I also had 8MB 16-bit fast in a GVP sidecar and 2MB chip, having an 18MB A500 was pretty nice.
Worked for years but I think my ram board finally crapped out, the past year or so It's crashed when I tried to activate the ram on it. Oh well, maybe I shouldn't have overclocked it.
Should probably send it off to someone with more experience fixing these sort of things, but just haven't had any time for Amiga stuff the past year or so. Will take a look around for that RAM, anyway....