I have an old Addtronics 8290A (the older style from about '98, not the current one) that has no fans in the rear except for the PSU fan. I was curious if anyone has added an 80mm to the rear. It currently only has air flow holes in the back for a 60mm. Also the rear isn't flat, it's L shaped and there isn't enough room to fit an 80mm on either section (see pics), so I'd have to rig something up, like using an 80mm to 60mm adapter, if it'll fit behind the CPU/slocket (may not).
Some pics:
http://pichosting.pcthike.com/album34/rear_fans
http://pichosting.pcthike.com/album34/celeron_hsf
Not the best but I made them awhile back for other reasons...
Some pics:
http://pichosting.pcthike.com/album34/rear_fans
http://pichosting.pcthike.com/album34/celeron_hsf
Not the best but I made them awhile back for other reasons...