Do not purchase a dual Xeon system [at the moment] just for gaming [multiboxing or not], I was tempted to go that route myself but after finding some benchmarks that just turned me off to the price:performance ratio, I will definitely be waiting for Sandy Bridge.
Code:
Using EVGA's SR-2 and putting 2x 5680 Westmere Xeons overclocked to 4.37 GHz against a single
980X Gulftown overclocked to 4.72GHz.  $3400 in processors versus $1000... the results were not
amazing.

http://www.bit-tech.net/hardware/mot...-sr-2-review/1
You can argue that they didn't test more games, use crazy 17-way SLI, or whatever... but I would guess that the cost of such a system won't be justified by 6 boxing 11 year old Everquest or even 10 boxing WoW.

Sure you could buy a budget system with dual Xeons, but if $3400 in processors alone can't decimate a 980X [which is going to be replaced by some nice Sandy Bridge CPUs], then I would urge you to hold out as well. Or who knows, maybe the new AMD processors will finally make Intel price their new CPUs competitively [LOLOL].