I ditched my last RAM 3500 single cab build partially because the build costs (flatbed and camper most notably) were going to outweigh the value of the truck in the capacity that I had planned to use it.
Back in 2020 when I was planning this current build I spent much time comparing various configurations - single or crew, slide in or flat-bed, etc.
For my specific build my goal was to maximize the living space for the least amount of money. I am a numbers guy and the metric I weighed most heavily was price per cubic foot of interior space - this included price of truck, camper, flatbed (if needed), installation and transportation costs, etc.
The worst choice for me would have been a crew cab diesel with a short-bed, flatbed, and flatbed camper. For others, that may be the perfect combination but for me the single cab AEV Prospector built using a 3500 Tradesman long-bed with a slide in camper. Keep in mind, the cost for my brand new AEV Prospector and FWC Grandby camper was just over $75k and that included all labor, taxes, etc.