When I purchased my mill, I went through almost the exact same thing. My shop, at the time, was in a trailer and the ceiling was at a number very close to yours. A general caution that I learned in the process is that specs. can mean different things. So you need to be real careful about any specs. or even actual measurements that you are given. For a vertical mill, it is the MAXIMUM height that counts and that may not be the height that the seller lists. Many people think the most important height is the minimum that can be had by lowering the head so that it can fit through a doorway. That may be important and in some situations it may be the controlling/deciding factor. One place where I worked had a large, open area with a vertical clearance over 16 feet. BUT the tallest door leading to it was less than 7 feet high and that was a problem. Anything taller had to be brought in sideways or in pieces. A real PITA.
Anyway, back to my trailer shop. I knew that I would be there for several years before I could move into a larger shop, which I have now, so the mill had to fit, not only through the door in it's minimal configuration, but also under the ceiling at it's max or at least close to that. I also wanted to avoid certain things, like round column mills. I did have to do a lot of checking and looking, but in the end, I was able to find several models to choose from. The one that I purchased has a minimum height of 72.5" (not what the specs. say) and a maximum of 78" with the head at it's highest point on the dovetail column. We are not supposed to talk about such things here so I will PM you with further details. That model is no longer available, but there are many similar ones that are.
If you do not like the route that I took, then you just need to keep looking. There are suitable mills out there. Persistence pays off.
PS: I have rarely had to remove my drawbar, but my head does tilt 90 degrees so that was never a real problem. I did remove the drawbar on another mill to repair it and add a better thrust washer so I guess that could be a consideration.