Anything is possible with time, money and engineering.
Our '82 Jayco-SOB, had the similar setup. It had two upper bunks in back (not for adults) but it also had like the Airstream, two single lower beds under the bunks. In between the lower beds was a place to stick a post and on that post a table top so the back was not only a place to sleep, but it dubbed as another smaller dinette.
My parents still have the Jayco too, so if you are interested, I should see it this summer and I can take some snapshots of it.