We had the same problem. We eventually settled on a class A - Bounder 33C. It is 34' long, which is just a little longer than our previous trailer, but about 20' shorter than our truck and tt combo. It has 3500 lbs of carrying capacity, which is more than enough for us, 85G fresh, 55 gray, 44 black; that will last us a week.
The Cs we looked at seemed smaller for the same foot print, probably because the ceilings were lower. They also tended to have less storage, CCC, and tow capacity. We really didn't want an A but now that we have it, we are glad we do.
For fulltiming, one needs to strike a balance between size, storage, and space. One always has to be sacrificed for another.
Best of luck in your search! It took us a couple of months of contemplation to arrive where we are - in an A...
2015 Jeep Willys Wrangler
2014 Fleetwood Bounder 33C
States camped: all but Hawaii
more than 1700 days on the road