Length isn't the important factor, it's weight. Lots of light weight units out there that are 30+' long. Problem is when you start looking at light weight long trailers then you take a step back in long term quality. Those kinds of trailers are great for the campers that want to go 5-7 weekends a year a long with 1-2 week long vacations. They're not made for full timing. Construction methods and interior finishes are strong enough to sustain full time living. If you want to full time then you need to look at what you can get weight wise that's built for full timing. IMO after owning a similar version of your truck I wouldn't want to tow anymore than 6000lbs. 7000lbs is the upper edge. So back it up a bit and figure 1500lbs of stuff for travel. 6000-1500=4500lbs. That's the dry weight you should start with. Even bumping it up to 7000lbs and going with 1500lbs of stuff you're at 5500lbs dry. So now look for trailers that weigh that much to start with and find the best built. Here's an example of a well built TT that weighs a 5700lbs dry. You can order it with dual pane windows too.
Northwood Manufacturing: Snow River Floorplan
If you're going to be out full timing you're going to be wanting a rugged built unit. Northwood products build their own frames and have really high CCC. You can load them up and not worry about being overloaded and wearing out the frame and suspension.