I think my only concern would be trying to run a long SATA cable for the DVD drive. Any other problems?
Keyboard/mouse? Blutooth would run the 6-8 feet but how about through the floor? Maybe the receiver would need to be up in the cabinet.
Multiple USB. Probably just run a large powered hub in the cabinet for that too.
Thanks for the idea, it sounds a lot cheaper than buying a water cooling system.