I pull strictly Forest River trailers. There is a lot of different brands. Mainly Grey Wolf line. Not a bad trailer, kind of basic. Fiberglass sides are better for economy. Rounded fronts do well. Length really doesn't affect economy that much. Height does.
I find the long ones for the most part more stable. Fifth wheels typical do better for economy if you factor in the extra weight over a bumper pull.
That Rockwood was a really nice trailer.
Forest River owns Palomino (fan of the Sabre line) and Coachmen.
http://www.forestriverinc.com/Index.aspx
Usually you get what you pay for with these. The ones that cost more are better quality.
Not a fan of the V front trailers. I find those don't handle wind as well. The truck is cutting the wind, all the high V does is grab more crosswind.