I originally went to them discussing a 4U server i'd picked up, but as you probably know (I didnt then) it just didn't make financial sense. They offer U racks, but they also put a rack of shelves on them that can take the servers they build for leasing using mini-ATX cases (6 in the space of 4U). I just happened to ask them what box to use and rented that space instead of 1U.