Silverstone Fortress FT03 at $169 is worth a look it should certainly fit good sized video cards and a full ATX PSU. Obviously it's not for everyone, but it is pretty small. The Newegg page does nicely list all the dimensions so you can figure it out pretty easily if it suits your needs and if you like it in general.
The cables come out of the top. So it uses a similar design as the Silverstone RV02 and Silverstone FT02 so the motherboard and video card connector are at the top.
And then there is that grill on top that protects the stuff from dust.
Sandy bridge is worth it. It runs cooler and faster and overclocking is a breeze compared to X58. The pricing is also like day and night. $220 for 2500k the best gaming performance instead of $1000 for the 990X and in most cases the 2500k is faster. Then unless something is extremely threaded and takes big advantage of the triple channel memory the 2600k at $315 beats the 990X in non gaming scenarios.
Additionally I would steer clear of Intel mobo's and check out options from Asus, Asrock and Gigabyte, generally they are more features available on their boards.
It checks all three boxes listed in what you needed, is solidly built, innovative in how it places components and can be kept nice and cool with space for two 120mm fans in the front (for positive pressure cooling).
Word of warning, it's compact nature means it can take graphics cards of a maximum length of 10.5" with the power connectors on the TOP of the card. If the power connectors are on the side-end of the card (facing the front of the case) the card length can only be at maximum 9.5".
^The RV02/FT02/FT03 are all great cases (have the RV02), but a full tower case (MUCH bigger than the 900) is pointless if we're looking for small form factor computers. You may as well go full ATX at that point. My build easily weighs 30 pounds (before watercooling ). EDIT: I didn't see the OP's link to the Antec case, so I thought you were recommending the bigger cases. Oops :whiste:
Take a look at Silverstone's SFF cases; they have a few that can fit full size AMD GPUs (which are generally longer than NVidia cards). There was a great mini-ITX gaming build around here a while ago, but I can't ever find it again; I'll look around and see if I can't find anything similar.
In regards to your components:
It would help if we knew what you'd be doing with the computer. Then we could recommend more specific parts.
Go with Sandy Bridge. The 1366 chips are not only slower, but hotter as well. Considering the platform is going to die and how well the i5-2500K keeps pace with the 980x/990x, there's no reason to go 1366.
Why get a Velociraptor? You'd see better performance from a SSD as either a boot drive or a cache drive (only works with Z68). For a 64-bit OS, you'll need 64GB minimum, but a cache drive can work with 30GB.
That Corsair PSU is a bit beefy for one 570. Are you planning to add another?
You could probably do 650W if you don't plan on upgrading to SLI.
The RAM is good, but I'd try to find a 1600MHz kit if I were you. It gets a little better performance than 1333, and doesn't add much to the price.