Do you have to use xeon's? why not get some more efficient haswell CPU's over those ivy bridge CPU's and go consumer grade instead of server grade so you get more CPU/$?
If you MUST go with ivy bridge xeons
this motherboard will work but is about 3x what you would pay for a consumer grade motherboard.
Going with a i5-4570s would get you a quad core haswell core at 2.9ghz for 65w [link
here and cheapest mobo with 2 full sized PCI-E slots is
here]
the haswell cpu uses 15w less than your ivy bridge xeons, and while it has a lower clock speed than the ivy bridge xeons it has a higher IPC (instructions per cycle) so it will do more work at the same speed.
you can see
here sandy bridge vs ivy bridge vs haswell clock for clock speed differences. all CPU's tested are running at 3.5GHZ so you can clearly see the differences in speed between the different architectures.