Need suggestions

The reason you will have a very had time finding a walk-around bed in a short unit is that the rear overhang would be too long (making the wheelbase too short and the balance all wrong) to keep the wheel wells forward of the bed walk-around area. I would recommend checking carefully, including a good test drive (at highway speeds with some cross-winds and/or passing semi trucks), any relatively short unit you find with a walk-around bed. There's a greater than average chance that it may have characteristically poor handling. Although they are far less common, it is more practical to have two twin beds in a shorter RV (with a center aisle) and there are some layouts with that plan.

I know there are many reasons why people want shorter RVs. If the concern is that it is harder to drive a long RV than a short one, be aware that on the highway length makes next to no difference. It does make maneuvering in parking lots and tight camp sites harder, and incrementally limits the number of camp sites you can use in some campgrounds, and of course can be a big problem if your storage spot is not long enough. I guess all I'm suggesting that you not exclude longer motorhomes on general principle alone, absent some specific reason why you can't have one.