Purchase either 1 or 2 (for clustery redundancy) Xen hosts to replace dodgy old x86 PCs in the machine room.

Machines to run as a Xen:

• mussel
• mermaid
• mooneye
• coolstore (currently a Xen on mermaid?)
• possibly some of the other colo machines

There are a few possibilities for hardware. Nice Core2Duo machines can be purchased for around $1500. Sun Opteron servers are also not too ridiculously overpriced. e.g. a Sun x2200 with 2x dual core Opterons can be had for around $2500. They also have education pricing.