Take a look at Outdoors RV, Creekside, Titanium series line.
All Creeksides under 6000#, Titanium is their top of the line, in the weight class.
Outdoors RV Creekside/Titanium seriesCousin to Northwood's Artic Fox etc. 4 seasons, all aluminum superstructure, HD frame with off road suspension system makes them tow great. This one has the solar package installed. Thermal pane windows etc, They may not look high-end at first glance, but go to the mfr. site and watch the construction videos, a great job of explaining the product and the market they are trying to reach. You could certainly spend more, but I'm not sure you really get more in a travel trailer.
Example:
Creekside 23RBS Titanium