Hey Carl, wondering if you ever found a solution. I've seen some recent trailers (non Airstream) that have a "slip in board", for lack of an exact description, that is easily added and removed that would allow a foam temporary mattress to rest on top. This would basically cover the gap that now separates the two twins. Granted, the nightstand would still be exposed and not covered by mattress, but my thoughts were move our heads to the opposite end and at least have the ability to have one larger surface if wanted. I thought this might allow me to avoid all the work that comes with a true conversion. Which, by the way, i've seen done on this forum...it was extensive work, well beyond my pay scale! I'd love to hear if you found a solution.
1992 Excella Classic 29'
...2013 Chevy 2500 HD, 6.0 Gasser