Hi 'Ace!',
I think there are two objectives to be pursued for offroading: (1) Smaller is better, and, (2) less weight is better.
On the RV.net, you are going to have to adjust to a lot of bias towards _bigger_ is better (..."buy the biggest camper that money can buy"). A lot of people here will suggest that anything less than a Class C will not be comfortable enough in the back country. This notion of "bigness" directly affects overall weight, too, and weight is your enemy when negotiating difficult trail conditions. You will have a tough time finding an RV that replaces a Jeep. No matter how small you manage to keep the RV, there are going to be some places that are impractical to get a full sized truck into.
I don't have any problems with any of the brand names that have been mentioned, so far. The designs (roofs should crank up from the inside as opposed to from the outside) and materials (particle board is heavy and theoretically unappealing) have to make sense, though. You need to do your own due diligence in that respect.
I would point out that some manufacturers (OUTFITTER and HALLMARK to name a couple) are moving towards monolithic shell construction. While inherently more costly, they are less likely to come apart or to contain materials that readily become water logged.
While I prefer smaller pop-tops from a size perspective, note that as 'jefe 4x4' has pointed out, there is very little to recommend a pop-top over a hard side camper from the standpoint of "center of gravity", alone. In the back country, I would venture to say it is about as easy to flip an empty pickup truck as it is to flip one carrying a hard sided camper. Also, it is a myth that a softwalled pop-top has inherently less insulative value than a hard sided camper.
At the end of the day, while less overall size and weight recommends itself, there are a lot of options within those parameters. And just because an RV looks smaller, it is not necessarily lighter in weight. If you dig, I'd bet you could find 8' hard side campers that are lighter than some 6.5' pop-top campers. Your concern about departure angles compromised by too long an RV or by a "bed dress" are dead on. When in the back country, a short bed truck (...shorter is _better_) is best filled with a 6.5' camper and with no rear 'overhang'.
When buying new, is it reasonable to think you can get most t/c for $500 over invoice, $1,000 off MSRP, depending on time of year?
Huh ??? Most of these companies do not 'floor plan' - - you can't go in and buy one of their models 'off the rack'. Most of the companies are small shops that don't 'lay a keel' until they have an order in hand. Even after you decide on a base model camper, there are often myriad customization possibilities. Additionally different companies have different styles. For example, at FOURWHEEL, you can buy a very basic shell and build it out yourself. But once you customize it, it might end up costing _more_ than a basic OUTFITTER with more utility out of the box. So it is important (for your specific application) to have a vision of what you want to end up with before you start picking brands and models. There's no short-cut.
Before you commit to any particular brand, I would strongly suggest taking the time to visit a few factories so that you can get a feel for what is going into the construction of these campers (and for that matter, the people you will be dealing with). It seems to me that you have enough back country experience, already, to 'sniff out' design or construction elements that aren't going to work for _you_.