The Nexus is only sold factory-direct in northern Indiana, right? That might or might not be an issue for you.
Fleetwood and Thor each seem to have dual brands of the same units. Winnebago/Itasca as well. So without looking, you probably are right and those are the same.
I would definitely not want one with a rolled filon cap. I would want the molded fiberglass cap. The Forest River Sunseeker is a lot of bang for the buck, but it has a hybrid of molded cap but with the filon side panels, which bring that dreaded lower seam into play.
http://www.forestriverinc.com/images/interiorhome/sunlCLCfeat2large.jpg
