Tiffin changed hands recently. I don't know what may happen with them.
The most expensive, best quality? Class "A" makers like Prevost, Newell, and such. For class "B"s? Advanced RV comes to mind, but be prepared to have a quarter mill in hand for starters.
Something that will last a long while, with a low CPM? A custom Sportsmobile van. It may seem to have Ikea-esque furniture and may not be as luxurious than others... but they are made to last a long time. You can get what you want with them, so if the granite countertop is a must, they can deliver.
A class "C" that is built well? Lazy Daze foremost, then Coach House. After that, Phoenix Cruiser and Nexus RV.
Truck campers? There are some custom makes of those, so I'd look around and search the subforum.
As for trailers, I would go and find a place that makes custom horse trailers. These places don't come cheap... but they can make a trailer that will still be in operation while anything coming from most RV travel trailer makers would have long since hit the scrapyard.