Something rackable that can be managed remotely. Possibly someone can preconfigure it before going to the data centre?
Specifically, it needs to support VLANs, so it can have separate internal and external network VLANs configured. Attaching a serial port to it from the blade server will be impossible, so it needs IP management (ssh/telnet is preferred, of course, but we can always get to it via an ssh port forward if it's web-only) It'll also need a minimum of 10 fast ethernet ports + 1 uplink port, and it would be nicer if it had at least 16 fast ethernet ports + 1 uplink port (uplink can be fast ethernet or gigabit ethernet, doesn't really matter, but it does need to be copper). Each blade has two NICs (internal and external), and there are 5 active blades (2x www, mail, db, hoiho), and there are some (3 I believe) spare blades up there that would be very useful to be able to move services onto without requiring a callout, so being able to cable up all 8 blades at once is a sensible thing to do.