My machine is under 7’ tall and it works very well for me. I get about 3’ tall of a cutting area, I would need to break that 7’ machine height to get the full 4’. When I built my Maslow, I had to fit it in a 7’x14’ enclosed cargo trailer, and I believe that had a 7’ ceiling.
The other dimension I’d look at is your machine width. At 10’ wide, your machine is going to be the full width of one of your long walls. I’d recommend looking into those hinged machines like @dlang was suggesting, that could go a long way towards giving you some floor space back when the machine isn’t in use.
In another one of David’s posts, he made up this handy spreadsheet to look at how frame dimensions will affect your machine geometry. One of the nice things about the Maslow is that you can change your machine dimensions to fit a space. The trade off when going smaller is that it will limit your usable machine area. Take a minute and play with that spreadsheet to get a feel for what your machine will be capable of.