Just as an aside, I can't see the flat floor 5th wheels catching on. Seems to me that climbing six or seven steps every time you walk in has no advantage over three or four steps climbing in. Yes, I have to go up three steps to the bedroom/bathroom, but I'm in and out of the trailer more often than I go up the other three stairs. Could happen, but IMO there simply aren't enough pros to outweigh the cons.
It's always been one of the things I've disliked about motorhomes is the climb up every time you enter.