> I assume the next MacPro will use the 'Ivy Bridge' processor, it's not due out until June.  

Not the Mac Pros – they have never used desktop processors which are limited to single CPU socket, they’ve used the server/workstation Xeon chips.  Current Mac Pro’s use the “Westmere” and “Nehalem” series Xeon which Intel released in January 2010. These cores are based on Core i7 tech which was released in Nov. 2008 – there is lag in migrating new chip tech up the line.

Intel has released new Xeons based on Sandy Bridge Core were released in single CPU socket config last April and a couple of months ago for dual socket CPU config. So now would be the time to release machines based on them. Ivy Bridge based Xeons have not be officially announced. There are various rumors that Intel might have a mixed bag of both Sandy-Bridge based and Ivy Bridge Xeons this year, but either way, the Mac Pro’s are over a full generation out of date.