MB for 4 dual slot GPUs

This would not be necessarily for 4-way SLI, just 4 GPUs that require two slots each to mount.

ASUS MAXIMUS IV EXTREME (REV 3.0) LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 Extended ATX Intel Motherboard $309.99

4 x PCIe 2.0 x16 (single @x16, dual @x8, triple @x8, x16, x16 )

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

jaquith, you are correct. I did not specify but I meant standard SB. Was thinking I could use this MB for a mid-level SB now and by mid-2012 upgrade to IB.
Good answers, I will now have to determine what PSU(s) are needed to run this amp hog!
The Revolution looks to have a design for just such a set-up.

nikorr, the spacing of the slots does not look wide enough to allow for the 4th card, physically.
Am I missing something in the picture?

Regarding the PSU or PSU(s) the newer nVidia's e.g. getting the Quadro vibe or FirePro are more efficient and you might get by with a single large PSU.

Here's an excellent PSU sizer -> http://www.thermaltake.outervision.com/ IMO for Rendering use: 1. 100% TDP, 2. 100% System Load, and 35% Capacitor Aging next if it's on 7/24 then look at Gold or Platinum certified.

If you post: 1. CPU OC, 2. HDD(s) number, 3. GPUs, 4. other connected doodads I'll be happy to suggest a couple PSU's or Dual PSU's...

Still putting the list together won't be for rendering. Mostly a folding farm to begin. The GPUs will probably be something along the lines of GTX560Ti. The SB will probably be a i5-2500k only minimum OC'd on air for now. Minimum 8GB ram. Only one SSD, Crucial M4 64GB. These pieces will be gradually doled out to other new family PCs because several members need upgrading. The setup will probably start out with no case, sitting in a cold basement room.

IF you use it for more than folding then don't get the GTX 560's -- IF you SLI (ever) they're limited to 2-WAY whereas the GTX 570 can 3-WAY on a LGA 1155 (4-WAY on LGA 1366/LGA 2011) if the MOBO's also have the 3/4-WAY BIOS Key from nVidia.

I am NOT a Folding guru -- to most that do I'm more noob myself. I have seen a few Folding rigs with several GTX 560's.

Thanks. Any comments on the recommended PSUs?

Fixed - *** Duh me I needed to count and calculate PCIe 6/8 pins ***

4XGTX 560: (4*(2x6)-pin per GPU = 8 6/8-pin PSU)
$279.99 CORSAIR Professional Series Gold AX1200 - http://www.newegg.com/Product/Product.aspx?Item=N82E168...
<or>
$269.99 SeaSonic X-1250 1250W - http://www.newegg.com/Product/Product.aspx?Item=N82E168... ; 8 x 6+2-Pin

4XGTX 570 (Dual PSUs): (4*(2x6)-pin per GPU = 8 6/8-pin PSU)
1. MOBO/CPU/2xGTX 570's:
$ 219.99 SeaSonic X-SERIES X-1050 1050W - http://www.newegg.com/Product/Product.aspx?Item=N82E168... ; 6 x 6+2-Pin
2. 2xGTX 570's:
$139.99 SeaSonic X Series X650 - http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$14.99 Dual Power Supply Adapter (Braided / looks nicer) - http://www.frozencpu.com/products/11741 ; 4 x 6+2-Pin

Best answer selected by bwhiten.

Thanks again! A lot of research help for a stranger  

Good Luck!  

The ASUS WS IMO is the way to go, I've built off it and I know a lot of folks who really like it and have excellent experiences.