Actually I've seen a 600X with some 500MB of RAM upgraded to Windows 7, and I'm about 98% sure it has built in wifi because it has an extra window on the bottom and there's a chip underneath labeled "IBM PCI Modem with Voice".

- Upgraded 600X running Windows 7
EDIT: When I try to turn it on I get errors 161, 163 and sometimes 173. I THINK that means the CMOS is dead.