Need Suggestions on a Motherboard with 2x PCI-E X8 for Raid Adapters

Hi, I'm looking to build a NAS server with quite a lot of headroom for HDD's.

The problem is i have a hard time finding a motherboard with 2 PCI-E x8 that does not have x2 CPU's X16 Ram Slots and so on. I mean really you can get 4x PCI-E X16 Slots working at (x8 with all 4 populated) and you cant get a damn mobo with only 2x PCI-E x8 that works like it.

I only found Intel S5500BC

But its size format is not ATX meaning instead of the space available ATX=12" in × 9.6" that mobo is SSI CEB-leveraged 12” x 10.5” , witch is obviously 0.9 " too big.

The case is the Lian Li Modular Cube Case Black

And i want to use 2 of these 12x controllers to tie up 24 HDD's after i insert the Modular expansions i Gain 1x 3.5" for every 3x 5.25" so that makes 2x12=24HDD

The Controllers are Adaptec RAID 31205

The question is do you know of any motherboard that does not imply 2 phisical cpu sockets and has 2x phisical PCI-E X8 that run at X8 speed (as in 8x lanes)

or do you have any other alternative i looked into PCI-X as I've found a Cheap motherboard with 2xPCI-X but i cant find decent performing controllers with 12x internal.

Thank You for your time!

Supermicro make an atom board that fits your bill - X7SLA-H. Dual core atom, dual gigabit LAN, 2x8 PCIe (one 4x electically).

24 drives are going to suck a ton of power ...