Scott, that is exactly the way the computer installations I saw were wired. They brought the 3p panel into the computer room without the grounded conductor, only grounding for the equipment. The regular office space and the single phase (lights and 5-15s on the wall) in the computer room came from a separate single phase panel. The only thing we were careful of on the 3P panel was that the 2 wire L/L loads were not on the red leg.
