The 7200 is kind of interesting especially if it's the 120MHz variety. They're becoming uncommon because nobody wants them so they may not be rare now but they will be at this rate, especially since they suffer from plastic-itis like most other Macs of the era. They were also sold in small numbers in Europe housed in a tower case and rebadged as the 8200. They do have an upgrade option, an uncommon Sonnet card (or maybe two? G3 and possibly a G4) complete with its own dedicated high-speed RAM slots that plugs into a PCI slot and basically hijacks the system. I tried to buy one once but someone REALLY wanted the ones I saw for sale, paying over $200 for one and $400 for the other. I would've kept bidding them up but I wasn't really willing to pay that much if I did successfully outbid them (they're just a curiosity and I don't think I'd actually use it except as a gee-whiz sort of display piece). If they had just let me have the one with the broken RAM slot for like $80 I would've not bid on the other and let them have it cheap (we were the only two bidders on those auctions) but no, they had to be greedy, so I made them pay. Hope they're enjoying them.