Oxide's sleds don't conform to U sizes directly, IIRC. And even though I'm not there anymore, I can say for sure that it's not going to shrink to 1U: the larger size is very important for other reasons. For example, the larger sled size means larger fans, which means that they can be run at lower speeds, meaning less power draw, less wear and tear, and less noise.

> water cooling only.

There's some comments above about water cooling, I doubt this will happen, but we'll see I guess.