I have a pair of Scopema RIB "Neptune" single seats for sale. Scopema RIB seats are choices of many van conversions because they have integrated 3-point seat belt and crash-tested in Europe. The "Neptune" style folds down to form a single bed when combined with a swiveling front seat and/or a back cabinet depending on your height.
This youtube videos demonstrates how similar seats are incorporated in a "multi style" camper.
I bought this pair and had them installed by a Canadian authorized dealer/upfitter for my Mercedes Metris conversion. Unfortunately when I picked up the van two weeks ago, I found the seats are a couple of inches too wide for my van to make a passable middle aisle. So I have to re-draw my floorplan and sell the seats.
I got these seats 2 weeks ago so they are probably as new as a second-hand seats could be. I did see some marks on the metal frame likely from installation, and a small scratch on the back of the sitting area of one seat (fourth picture attached).
If you are interested, please PM me.