I want to see a 20' full featured camper (may as well get a shower inside too unless you love showering out where the world can see......weird) come in at 2000lbs.
My empty 20' boat trailer with only 4 2x4 bunks on a bare frame weighs like 1200lbs and my old 16' ALL aluminum enclosed bare bones snowmachine trailer weighed about 1000lbs.
That would be the perfect travel trailer for sure. Heck that would be 30-50% lighter than most truck campers with the same features and they don't even have full frames or wheels.
The perfect camper like this will be made out of unobtanium because titanium is too heavy! However most are made out of Chineseium and much heavier.