Many threads over the past decade have been written on the C forum on optimization compromises in fitting a bed, bath, den, and kitchen into something 24 ft long or less.
The prime impetus to keep it short is usually to go toadless. In essence, if you can remove the bed from the floor, you gain A LOT of shortness (like down to 22 ft).
If you go w/ a cab over bed, it is easy to keep the rig the size of a truck camper, and the queen bed is then permanent, though very elevated for adults.

For B+ rigs, short goodness comes either from a drop down bed, or a den-to-bedroom conversion -- so common. Mine is one of a thousand copies of this very efficient plan. I think one of the Ducato Trends somewhat mirrors it, and adds a drop down on top of that. At 24'+
All I would submit is that it is very easy to do-undo a bed from dinette/sofa. And I'll bet it's as easy to crawl from this super king bed as to get out of the drop down 'queen' for those increasing (age) needs to nite potti.