Thanks guys for the feedback. I may be wrong but it's sounding like higher end machines tend to max out at around 10 accounts. As I could run 10 on a relatively old Mac Pro it seems that for multiboxing, hardware technology advances have not produced significant game changers. I would imagine the frame rates are slightly better and of course multitasking and video has come a long way but I'm interested in more accounts per machine.

It also seems that the Mac Pro may be the wrong tool for the job. There are obviously many unknowns at this point but it seems clear that the FirePro graphics cards are just not the right choice for multiboxing.

As for the cost, I may have been looking in the wrong spot. I was comparing a slightly customized Digital Storm Aventum II H2O Level 3 Performance PC to the new Mac Pro as customized above. Digital Storm is known for creating the PC Gamer Large Pixel Collider which is described as "an irresponsibly powerful" gaming machine with "uncomfortable power". The specs I came up with above are a scaled-down version of the LPC, which is actually slightly more expensive than the new Mac Pro. I'm guessing now that there is a ton of markup.

As I'm a bit nervous about building my own machine I'm looking for a solid performer that I can use for years without too much trouble. Maybe building is the best way to go. Now I guess I'm looking for 2-3 of them. Do you guys have any suggestions? Thanks again : )