Well, I figure that the folks going air-only can figure out pretty easily if their prospective components will fit - we basically spell out the maximum dimensions for each component on our site, so you just need to compare a few numbers. They won't need us to verify anything.
With water cooling, comparatively, it can get complicated since you've got many avenues to try, and you have multiple potential components vying for the same space. You can't just compare two numbers; you have to do a bit more math to determine if a certain arrangement will work. Thus, you're more inclined to ask for advice! (And understandably so)
I mean, if people only want one graphics card (with a block on it, at that), and the ability to overclock like a madman, then go for it! Maybe it isn't what either Aiboh or myself would build, but the whole point of Cerberus being a flexible enclosure is that it enables even some of the fringe builds like that to be possible. So to each their own 
(I also think that a next gen dual-GPU card in that sort of a build - if we are graced by one later in the year - would be very, very interesting...)
