Oddly enough, back when the cylindrical Mac Pro was first announced, a coworker and I discussed how exactly one would rack them. We came up with something very similar, but slightly asymmetric, and designed to hook into a standard 19" rack.
(This was prompted by the question of what Apple's Web site runs on if they don't make servers any more.)
(This was prompted by the question of what Apple's Web site runs on if they don't make servers any more.)