The P4 system I want is sold out and has been sold out for a few days now, not asking when they will be available again but generally how long does it take on average to have more systems back up?

I would keep checking because if a customer cancels a server (or has it taken away from them) it goes back into the order form which can happen at anytime.

I was in the same boat so to speak - I just ordered a Dual XEON Cpanel, after it being sold out for a while, one day it just popped up '1 Available'.

Not sure if it answers your question because maybe they are going to add lots of brand new machines soon and you want a date.