Can't find TC meeting my simple need.

Take a look at Northstar Campers. Not so sure about the east/wet bed in the lower camper but I do know Northstar is more than willing to make custom modifications. I'd be very surprised if they aren't willing to build whichever model you choose with a closet instead of the wet bath. The floor insulation could be a little better in mine but that was easily fixed. The insulated windows are amazing at keeping the cold out. The biggest problem may be a generator compartment. Maybe you can talk Rex into building a box where the cassette toilet would be. Or, do like I did and build out a genny box for the front hitch.

PS: Welcome to the forum