NudeRaider -- if you want you can combine the physical variant with switches to have them move slots in a random fashion instead of slot-machines style. However I'd try that only when one of the basic variants works.
NudeRaider -- But if you don't want or need the players to see a physical representation of the shuffling on the map, then just listen to dem0n
NudeRaider -- the thing really shouldn't be too difficult. using a buffer location you move all buildings 1 slot (I think you have that done, from what Ive seen). Then if make a trigger ABOVE the moving that's responsible for assigning building in the selector location when the CHOOSE conditions have met and the selector slot isn't empty. Clear choose conditions. Then make the SAME trigger BELOW the moving triggers, and voila, you can't end up with an empty slot and it's all done in a single loop, with just 1 redundant trigger.
O)FaRTy1billion[MM] -- I don't actually know what level I was, but low enough that it was too hard to kill them
O)FaRTy1billion[MM] -- reminds me when I was level like 4 or whatever and every time I'd try to fast travel to riverwood a dragon would spawn and then kill all the NPCs, so I never went there