I actually hadn't considered the square hogback floor - I've slept a number of nights in it's little brother (the scarp 2) which is very nice and roomy, but you lay lengthwise with a door next to each side - with the hogback you'd be able to orient the other way so you can all get to a door without stepping over each other.. that's not too bad with a couple kids.

I'd still try rigging a couple two person tents as "rooms" with a tarp "common area" in between