I'm in the real estate business and know most of the angles, so I am just speaking from common sense as well as experience. A good commercial space is very costly, and a dojo (unless well established) does not bring in enough to cover a mortgage payment on this type of space. Even with interest rates at record lows, the economy is pretty shaky, and I for one would not want to risk my one safe haven (my home) for a mortgage on a commercial building that I could not pay for, and might not be able to rent.
The best scenario I've seen so far is having a dojo on your own home property, but to be viable you need to have enough land, and zoning that permits this type of use, as well as decent visability. This is one of those options that I am always looking for, but the right property hasn't presented itself in a price range I can afford.
Glad you are so enthusiastic! Brain storming is what we all need to do.