Many manufacturers used to provide two singles or perhaps twins as an option. I suspect the market for that configuration is quite small. I for one would have liked to have that option in my Newmar versus the queen. I think some do have the option but can’t remember which ones.
One of the main problems is that many of the queen/king setups are in a slide with the slide mechanism being under the bed. If the bed is not in the slide then they use the space for tanks, electrical or other support stuff.
Good luck
Tom Wilds
Blythewood, SC
2016 Newmar Baystar Sport 3004
2015 Jeep Wrangler 2dr HT