Typically standard widths of travel trailers will be no more than 102" or 8' 6" which should include any and all items which may stick out past the walls like wheel well skirts.
102" is typically OK to haul without permits so manufacturers tend to build no wider but you might find a few wider ones..
For narrower trailers, you will need to look at "lite" or light weight models. Manufacturers tend to build these a bit more narrow than regular ones which allows them to shave off some weight and some frontal area. Typically can find those as narrow as 7'..
Oops my bad, looks like you are asking about width but at the end you mention height..
Many TTs are under 10ft including the A/C unit.. However 5th wheels tend to get very high so if they are looking at a 5th they will have abit harder time finding one at that height.
I know my 26 ft TT roof deck is just a little over 8ft high since I use a 8t step ladder to get on the roof. Add a little for the A/C I would say I am just under 10ft..