I considered that with mine. Got about as far as thinking if I really wanted to do it right, I'd need to turn the other 8-bit ISA slots into 16-bit by soldering on the additional connectors, so I could use video card, sound card, etc. The connectors can be bought all day long on ebay for like a buck, but all that extra soldering... ugh! Dang you cost-cutting Commodore! 
The hardest part wasn't the soldering, it was the disassembly and assembly of the A2000.
Most SBC come with Video card and LAN and all IDE, floppy controllers, so you only need a good Sound Blaster sound card, and also I wouldn't bother with a 486 SBCs, it's just too slow.
As far as the A600 for being the worst, I think it was back then, when compatibility was important and HDs were expensive.
Now, A600 is one of the more desirable Amigas, because includes the IDE, PCMCIA, color video out and it's compact. You can get fairly priced accelerators, mem expansions, run WHDLOAD games, etc.
One problem I have with A600 is the crappy CAPACITORS :furious:
