| Yea, eVGA is really anal about that stuff. You can't even replace the stock fan with a nvsilencer or accelero, let alone a water block, if you want to keep your warranty. BFG doesn't have that problem, don't know about other brands.
Strangely enough, eVGA sells video cards under the 'Black Pearl' moniker with a water block factory installed, but they are only available in Europe. | 