Only problem I might see is ground isolation. Sometimes (well it depends on manufacture) the amps are not suppost to touch because of isolation problems, and the way you have it will make a solid connection between every chassis (unless you have some type of rubber grommet with the screws). This would be just on the amps, because the xovers are plastic. Just try this, get a multimeter set it either on Diode test or Ohms, and put one prong on one amp and the other on the other amp if you get a beep or a reading (if set on ohms) you have a connection between the amps. Which like I said may or may not cause an isolation problem. Dont take my comment too serious am I might be full of myself, lol but try it.
Otherwise LOVE IT, I thought about covering an eclosure with that stuff, its just too expensive and you would have do some extra stuff to make sure it stay on there though.