3. I heard that some cases may be unable to house larger components such as high-end graphics cards. Which of these cases can house high-end graphics cards (e.g. 4890/5970 or 295GTX) under crossfire or SLI?
4. Which will be the most noisy? And how noisy will they be?
The Xclio a380 will cool the best, have the most room, and likely won't be much louder so I say go with it. Xclio cases are known to cool well, but watch out for sharp edges.
All that said, the thing is ugly, in my opinion.
This case however, has better cooling, if you buy 2 120mm fans, is quieter, and is made by the highest quality computer case manufacturer in the business, Lian-Li. It also looks a hell of a lot better.