Another point is that putting the shower in front of the entry door seems to be a fairly common (though by no means universal) practice in European campervans.
Personally, I think it's a good idea. That wall of the shower would be wasted flat space anyway, and if you don't combine the shower and door, then you need to have an extra couple of feet of free wall area somewhere else to put the door (and perhaps, the steps). I'm a big fan of using the head area as a mudroom.
My gripes with how it's often done in the Euro trucks is that the shower pan in the entry is usually dinky (I'm a big gorilla) and there is often nothing but a curtain separating the head from the rest of the cabin. Perhaps that's okay for couples who are used to living in each other's pockets, but I personally wouldn't want to have nothing but a curtain between me and whoever happens to be taking a dump - I'd much prefer having a hard wall for privacy and a separate "fart fan" for exhaust.
