$2000 build for Blender modeling / rendering

Looking to build a high end rig optimized for Blender modeling and rendering. I'm particularly interested in rendering performance, and I'm having a little trouble understanding the following:

http://blenderartists.org/forum/showthread.php?238202-BIGGEST-BLENDER-CYCLES-GRAPHICS-CARD-FAQ-s

I would like at least two nvidia cards, and I'm a little confused by the second post in the link above with regards to PCIe lanes. Is there a mainboard anyone can recommend with two PCIe x16 'electrical' lanes? Help!