Inexpensive (used) hardware for Xen virtualization test

Virtualization is one of the areas where I could really use some experience. I also run quite a few services (web, mail, dns, etc.) out of my home. Since most of my hardware is getting a bit old (I'm running on stuff that was surplused years ago…) I decided that it's about time I start renewing some things, and also play around with virtualization a bit more. My plan is to setup a SAN box (simple iSCSI target, relatively inexpensive gigE switch), get a pair (for starters) of new servers, and start building some new stuff with Xen, specifically planning on playing with live migration and full virtualization.

Does anyone have recommendations for used, older "servers" (really anything in a rack-mount form factor, I'm not too worried about things like iLO/iLOM for the test nodes) that support VT-x/AMD-V? I'm biased to HP, but it looks like they didn't make Proliants with VT-x/Vanderpool processors until G6 (for the DL360) or so, which is way out of my price range.

I'm looking in the sub-$300 range (or less, if possible), used, probably Ebay.

Any recommendations are greatly appreciated.

Edit:And, to catch this before the comments start coming – these are personal systems. I have first-generation Proliants still in use (I got them as corporate surplus in 05, they've been running since then, and probably were running since 01 or 02 prior to being sold). I don't need anything shiny and new – I've got a bunch of old boxes, at least one complete replacement for every model in use, and that's fine for me (and easy on the wallet).