If I went SFF with high end video, you can bet it would be inline style watercool, because in my experience any gamer SFF is inherently extremely loud to be cooled properly (and IMO properly for ANY cooling method means never, ever getting over 70c on any core be it video, cpu, chipset, et al).
I have an in-win slim microATX case (linked to above) and since I set it to PVR duties (M780 and GBPVR with xvid auto recompress) I had to put in a high CFM 80MM panaflo to keep it from auto powering down when 70C core is reached. I really wish I could afford to water cool it or perhaps put it into another (ATX midtower) ultra wizard case and beef it up into a combo PVR and fileserver.
As for those cube style SFFs, I always hated how they looked - except the ones based off of the shuttle XPC style cases, such as the morex venus...but those aren't even uATX, they are mini ITX, and as for PVR duties and such, that's another whole ball of wax performance and cooling-wise then uATX stuffers.
I actually do like the silverstone cases (the ones I have seen, which are basically desktop style midtower size full atx PVR cases) but they are a little rich for my blood.
To be honest, I am actually considering dumping the whole ball of wax, selling off every computer part I have, and getting that new alienware 15" laptop, but I seriously doubt all my comps will sell for enough to get the one with the parts I want in it. The new 15" alienware is very impressive for price, performance, and for once actual decent looks.