It looks like the 29QBS and 31 QBDS have double bunks. We actually bought a 2015 31 QBDS and love it with the exception of a few quirks. The door is held open at a 90 degree angle with a plastic clip that breaks in a small gust of wind. Also, the grey tank handle is under the slideout so you have to fashion a long handle to reach it or crawl under.
The outside kitchen appears to be optional in the two 2016 models referenced above. We wanted to purchase the 29 QBS layout last year but the outside kitchen was standard and you could not get it as 4 bunks so we went with the 31 QBDS. In looking at the Jayco site, we see the 29 QBS now as four bunks standard with the outside kitchen as an option. If you have talked to dealers and they are telling you there are no four bunk trailers, I defer to you and them. Good luck!