It should be noted that the LGA 2011 processors that the Mac Pros will use aren't scheduled for release until Q4, so Apple getting them 2 months early seems unlikely.
But there is the LGA 1356 Xeons due 4th quarter which is the 1-2 Package socket for the same series.
Interesting thing with both these new sockets the PCIe controller moves into the main CPU package. With 32x PCIe coming out of each chip direct if Apple needed to change the design of MacPro anyway.
The current design with processor(s) on a separate board that linked into the main board which had the PCIe controller on it. It would seem like this would need to change some what to use the new processors.