A forum post over at tonyx86.com has a Hackintosh system running the new Xeon E5 processors. The CPUs are expected to be in the next update to the Mac Pro. The specific CPUs used are dual Xeon E5 2690, which includes 8 cores each at 2.9 GHz. So, a 16 core machine.
Geekbench scores came in at 41,000 running in 64-bit mode under Windows 7. Unfortunately the forum poster hasn't gotten the OS X side running to full capacity yet. Likely, things will work better once Apple pushes out an OS update to accompany new Mac Pros.
To give some perspective, the current top end Mac Pro is officially recorded at 24,159. The current top end iMac is listed at 12,575. Such a Mac Pro upgrade suggests some impressive CPU crunching. But, hold on to your wallet, the E5 2690 retails for $2040 each. That's around $600 more than the original MSRP of the X5670 in the current top of the line Mac Pro. Even with volume discounts, Apple will tack on their margin, which all suggests the new Xeon E5 processors may push Mac Pro prices even higher.
A forum post over at tonyx86.com has a Hackintosh system running the new Xeon E5 processors. The CPUs are expected to be in the next update to the Mac Pro. The specific CPUs used are dual Xeon E5 2690, which includes 8 cores each at 2.9 GHz. So, a 16 core machine. 
