Xeon E3's are rebadged and binned i7's that are compatible with most motherboards out there.
Readycache drives can be used as boot drives but require additional fuckery in many cases, so I am not going to use one in my build list. I refuse to use BioStar or Diablotek anything due to reliability. I could not find information on most of the Biostar motherboards in reference to the latest shipping units requiring a BIOS flash or not, which is another reason i chose the ASRock or alternatively MSI models. This is important as it would require additional time, fuckery, and another CPU to accomplish. Notice the compatibility flag on his.
That being said:
http://pcpartpicker.com/p/1W14wBase Total: $357.95
Mail-in Rebates: -$25.00
Shipping: $4.99
Total: $337.94
Though, all of the ones using the Kingston module should add an additional 99 cents as the Amazon one has one left and requires 35+$ spent to have free S/H on that item.
I can configure for one retailer if you like or mix parts better for no MIRs. If you buy today it would be under 320 with code NAFSAVE25NOV1R shipped totally from newegg and also assuming a free shoprunner account.