im having trouble finding a case for this motherboard

[MachineGod]

hello, after years of window shopping and reading. im finally going to be building a computer.
it might seem a little over the top but im going to be using a asus KFN5-Q/SAS serverboard.
http://ca.asus.com/products.aspx?l1=9&l2=39&l3=575&l4=0&model=1868&modelmenu=2

basicly, its a quad processor mobo designed to use the AMD 8000 opteron cpu's.
it also measures 16" x 13"...

asus's website says it is a "proprietary" form factor. and im confused by this because when i try to find a case for it on there website, i can't. i haven't really found a listing of there server cases so maybe im not looking in the right place, but idk..

ive searched around and most of the cases out there aren't bigger than E-ATX,
i have found these 4U tower cases at http://www.supermicro.com/products/chassis/4U/?chs=748.
they look like they might work, but the "proprietary" thing has got me worried that it might not .

anyways, im just wondering what were these mobo's exactly supposed to go into?
i'm guessing a 4u rack mountable case. i was hoping a tower style case would fit it and i wouldn't have to worry about a whole rack mounting system.. but if thats all that will fit it..

 

[Platano]

Google Search shows these:

http://www.rackmountpro.com/product.aspx?prodid=1229&catid=206

http://www.rackmountpro.com/product.aspx?prodid=1224&catid=208

http://www.rackmountpro.com/product.aspx?prodid=2243&catid=208

http://aicmicro.com/product_Form_detail.aspx?ProductId=01400834&selection=4&Pc_PartsId=014&MainPage=

They all seem pretty pricy but then again this is for a quad board.

 

[E.T]

That motherboard might fit to WTX form factor, at least it's slightly smaller than its max size.
http://en.wikipedia.org/wiki/WTX_(form_factor)

Would be worth asking that from Asus because if it fits to that then CM Stacker 810 would take it:
http://www.coolermaster.com/product.php?product_id=13