Newegg has a couple of motherboards at:http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010200302%201071346469&name=Dual%20LGA%201366
You can't buy standard Core i7 processors though. You'll need the "Xeon" processors. You can find the Core i7 ones at: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010340727%2050001157%201652846898&name=Nehalem
Avoid the 550X series as they don't have HyperThreading. If you are looking to build a gaming PC, these probably aren't a good idea (You are probably better off with a desktop core i7). Also make sure you get the right RAM for these. Be aware if you only buy a single processor that you can only fill half the RAM slots.
Make sure you do your homework (With Motherboard Factors, Power Supplies, Audio), or you will get burned.