I think if you just shortened up the tubing between the cpu and gpu it would make a nice smooth curve and look fantastic. If you group up your pci-e power cables and keep them tight it'll look great. Maybe if you take a 6 pin and 8 pin from the midplate up to the bottom card and then run the other 6 and 8 pin behind the motherboard tray to the top card that could make it looks really clean. I know Charles did the Fried Chicken build like this and it really worked out great.

I can second the note about the secure tubing. After rebuilding my loop I had to cut the tubing off, I couldn't get it to come off otherwise.