DFI seems to have decided that the 244x244 mm mATX formfactor just wasn't big enough for its Nvidia nForce 6150/430 based Infinity C51PV-M2/G motherboard. Although this looks just like a mATX board at first sight, it's not.
At 264x244 mm this board is actually too long to fit into a mATX case. Someone at DFI must've had a stroke of genius when this board was designed, as you get a small board that doesn't fit in a small case, uhm, right...
DFI has been doing some interesting designs on its Lanparty boards for some time now, but this really takes the biscuit. There is at least onboard DVI and Component Video output so it can be used with HD displays, but you're going to have to put in a much bigger case than it really needs.
Product page here