Most ambulances also have a roll cage welded in the upper part. I guess that safety is a trade off for interior height wind drag etc. and from what I know. Some spots you could never reach if your height is past a certain point. ?
welll sorta.. the aluminum box is just strong..... usually 2" square tube framing.... older ones have these centered every 12".... newer every 16 like houses. To keep structural integrity yet add a raised section you just got to use smart engineering.... just like "properly" engineering a new door, window, skylight etc. into a home's wall/roof.
Don't forget about looking to see if you can drop a floor in places. This is why some put the shower in the drop area of the side door. They figure about only place they need to stand is in the shower.
Here is a video of a 6'1" fellow whom did just this in his ambo build
