You could mount it outside of the door and mount the fans inside, giving you air cooling blowing on the mobo and graphics memory chips (albeit warmed air slightly). This would also position the rad entirely outside the case, which should let ambient air reach the sides of the rad casing, which doesn't happen inside the case. It will look a bit odd, but you could dress it up. Just leave yourself enough tubing length to let you open and service the thing and you should fine.
Yep this is totally theoretical
