There are a fair number of low-volume and direct-to-consumer independent manufacturers. The other list is of the major brands that you're more likely to find at a local dealership.
Smaller independent manufacturers off the top of my head:
TTs:
Scamp
Casita
EggCamper
BigFoot
Oliver
Taylor Coach
Class B:
Leisure Travel Van
PleasureWay (might find these at a dealership)
RoadTrek (might find these at a dealership)
Sportmobile
Class C:
Born Free
Coach House
LazyDaze
Phoenix Cruiser
ProVan
I'm sure there are others (Class A?)... Many of these are known for making expensive, higher quality, products in low volume. You're not likely to find most of these at a local dealership.