I haven't looked at VM ware or virtual machine in a while, but back then, they did not support the use of directx. That kinda killed using virtual machines to play games on. But, things may be different now.

I don't see a reason to buy/rent static ip addresses. That's what a router is for.

$1000 for 6 pc's? I'm not aware of any systems you can buy for $165 and run 4 copies of WOW on.

I don't have enough information to speculate what you mean by renting a server for $200 a month or its purpose. Your wow subs will be $360 a month alone. Your budget just seems a bit weird to me. You basically need a big enough internet pipe to handle the up and down stream from that many clients and whatever amount of hardware you want to use to run it.