It's not unknown that Nvidia cards don't even pay for their own electricity. I dont know why this would change just because you're mining with 18 thousand Nvidia GPUs.
What's the difference between mining with 1 and 18 thousand Nvidia GPUs?
In the latter case, you are losing money 18 thousand times faster.
Someone should tell davidspitzer that he does not really want that to be his mining rig =:)