Just wondering if, for a second, you considered that repasting or replacing fans is a large effort for normal folks who just want a video card?
What kind of question is that.
We use a case based cooling system. ie: an enclosed box with fans. 12 cards in a box. This is lower power, fewer fans (5 instead of 12), and better cooling than putting fans on each card. Also easier to replace a fan on a case than a card.
At my scale, water cooling doesn't work and isn't cost efficient. Air is a surprisingly great cooling system.
It might work, I don't know... airflow on the box itself wasn't enough, but there were 12 cards in the box, we also had to have external airflow as well. A single card probably wouldn't be too much of an issue though.
That said, we aren't parting out single cards... it would be more like if you wanted to buy 5-10k of them. ;-)