I've seen it done for a small child, but not for a teen. To support the weight
., it'd have to have some vertical supports, making the already cramped dinette bed even tighter. It'd be a pain to set up and take down, and the pieces have to be stowed somewhere.
We have the same issue. I'm the early-to-bed, early riser in our family of 4 in a Scamp
13. I take the lower bunk. It's cave-like, so I can sleep while the rest of the crew stays up reading, cross-stitching, or watching a movie on a tablet.
In the morning I make coffee on our camp stove outside and sit or go for a walk while the others sleep. If the weather's nasty- a rare event- I can sit and read in the tow vehicle, maybe catch some news on the radio.
The trailer is our bedroom. The outdoors is our living room.
A Clam shelter with wind panels makes a nice outdoor sitting area if bugs or rain are an issue.