Lot of 25-50 Dell GX 280's 2.8 or faster, no mini-tower

25-50 Dell GX280 (other models are OK to as long as they are Dells). 2.8ghz min. speed.
MUST have XP COA's
No mini-towers. SSF or desktops only.

Here's the specs I'd like, other may be OK.
512 megs ram
40 gig hard driver (larger is OK)
DVD-rom driver (CD-rom may be OK

I can arrange my own shipping as long as you can put them on a pallet.

I am looking for wholesale pricing, so please don't send me quotes with retail prices.
Thanks!