Well, obviously no one wants to answer your question as we just keep ignoring your specs, but it is for good reason. You have seen alot of people encouraging you to get into pc builds yourself, not because you need this info to multibox, but because you can save alot of cash and get a better system for a mimual amount of effort if in the right hands. another reason you won't find alot of prebuild advice is because the experience isn't here except for the people who are willing to pay out the arse for alienware, and others alike. However, you seem intent to go about this with the spec you provided, so I will assist as best I can / as best it pleases me .

prebuilds tend to cost more for i7 technology than AMD's do. so even though its not recommended, go with an AMD build if you must do a prebuid at this price point.

tiger direct $769, pre shipping handleing http://www.tigerdirect.com/applicati...038&CatId=4928

newegg $899 plus 19 shipping / handeling for my zip code http://www.newegg.com/Product/Produc...82E16883229221

Honestly, didn't spend too much time on this as it isn't really something that interests me personally. You can be cheap with multiboxing if you can do some component installation or complete builds. But if you must buy prebuilds, then you aren't going to come in at the price point you have and still have the expectations you have. These two should get you by though you may still have to limit your framerates on slaves and make sure to not have too much visual candy settings turned on those slaves as well