At this point (20 cases) you require a lot of space. A Tournelle (sp?) stack would be more appropriate, and for better heat dissipation orient it so the boards are vertical.
Right now you can usually get a m/b/CPU from Fry's for about $280 every couple of weeks. Add ram for $25
Add a power supply for every other one, netboot and run off a server. You should be able to get an easy 3300ppd per system w/o OC, and you could probably get about 30 systems.
However if you really want to do it don't stick your money in the bank. Buy one or two as soon as you can and put out an extra 7Kppd.
Also - remember that every watt of heat in the summer needs to be cooled.
/edit - or just buy Dell's
I just got a Dell 530 Q6600 w/ 250GB HD, DVD R/W, mouse, K/b, 1GB RAM and 3 yr warranty shipped for $460.

Right now you can usually get a m/b/CPU from Fry's for about $280 every couple of weeks. Add ram for $25
Add a power supply for every other one, netboot and run off a server. You should be able to get an easy 3300ppd per system w/o OC, and you could probably get about 30 systems.
However if you really want to do it don't stick your money in the bank. Buy one or two as soon as you can and put out an extra 7Kppd.
Also - remember that every watt of heat in the summer needs to be cooled.
/edit - or just buy Dell's
I just got a Dell 530 Q6600 w/ 250GB HD, DVD R/W, mouse, K/b, 1GB RAM and 3 yr warranty shipped for $460.




