You listed the Rockwood Ultra Lites as one brand you are looking at. I might suggest checking out the Mini-Lites (same brand). Flagstaff may have a twin brand as well - they do for the larger ones. We just traded "down" from a large Flagstaff to a Rockwood Mini-Lite and this brand may have what you are looking for. (Our TT is right around 26' total length, but they do make Mini-Lites in shorter lengths.)
Some good advice you've been getting so far. To keep the cost down, look into used trailers or even last-year's model - some dealers are giving some good discounts on them, to make room for the newer models, due out soon.