Honestly, if they built a proper watercooling case that wasn't as excessive as the upcoming TJ12 (e.g. the 6 double-slot card case WITH a space in between each card), but still had the signature rotation of the mainboard, i'd buy one in a heartbeat. I liked that about my RV01, but unfortunately it was just too crowded in the end. The door on it was also borked and didn't slide all the way up without help. It also tended to unlatch itself for no reason and so it'd go halfway up before stopped.
I realise their RV02 has some support for radiators, but last i read it wasn't exactly suitable for proper watercooling due to the bottom having an extrusion preventing fitting of rads down there so it's very limited in what you can do with it.
Likewise, i like my 800D very much but it was also too limited in watercooling capability and absolutely awful at air.
However, if someone combined the RV01, 800D (particularly for the chamber divider in the middle), and then expanded upon the watercooling support, it'd be a real consideration. You know, dedicated space to mount pumps, perhaps sell different swapout accessories for different pump models (thus eliminating the need for the stands and heads), enough space for a 3.140 rad (with 120 support too) as well as a 1.140 seperate space at the back, and large enough to fit in 10 3.5 drive bays and 4 5.25" drive bays, and 25-50mm of clearence behind the motherboard tray (along with a load of rubber grommets to feed cables) i think it'd be the ultimate case. It's just come down that none of the big companies investing in such a case.
Still not heard any plans from Corsair on a new case though. They recently announced both the Carbide 300R and Obsidian 550D, but neither of them are supersized cases. Silverstone also have the RV04 on the way (
http://www.4gamer.net/games/017/G001762/20111008005/) but again, it's a smaller case.