I don't know if they're still around or not, but try using one of those SIMM adapters. I was given one that was a prototype, designed by an engineer at NASA and other than being a bit cramped for space, it ROCKED.
I bought one of those when they were sold through Amazing Computing Amiga Magazine. Paid about $50 for it. A good investment at the time. It was designed on the Amiga 3000, by an Amiga user, for the Amiga 3000.
They were never really mass produced and the guy I bought it from sold the design rights to it, IIRC. Not only will it take 4 4MB 72 pin SIMMS, but it will also use 2 8MB 72 pin SIMMS (that's how I have mine configured). But with the 8MB SIMMS, you can only use 2 of the 4 slots (makes sense).
BIG WORD OF CAUTION: If your A3000 uses a ROM Tower, you may wind up having to make a custom cable
like I did just to move it out of the SIMM adapters way. Otherwise the two will not fit. If you don't have the ROM Tower, then it's no problem. The best bet is to pick up some Zips until you decide if you want to add an accellerator or not.
