Sounds like a sweet setup. There's a guy in MN that had the "million dollar idea." He built storage buildings with individual units and then divided the units into condominiums.
Boat RV Storage in Minneapolis . I bought my first one from him in '04. It was 45' deep by 18' wide, 16' high. Worked great for our first rv. Then I decided I'd need more room so in '07 I bought a double (actually two seperate properties with no wall between) 18' x 90'. Full size roll up door at both ends. These units are insulated and heated, all have 60 amp sub panels and a handfull of recepticles. Dump station outside. Common bathroom. 60' from door to next building. Fenced with electric gate entry. It's 35-40 minutes from my house. You can pretty much do what you want inside your unit, within reason. There is an association (I'm a board member, big deal, get yelled at by the rule breakers sometimes, even threatened by one of them but he's gone now). Dues are pretty reasonable. Taxes are way too high because the assessor classifies them as "commercial" even the ones that aren't used for commercial (I'm actually in the middle of a huge legal battle over that). There are at least 5 of these type of developments in the Minneapolis/St. Paul area. Now, you guys have the info. A business idea for somebody with some capital to build a site like this in your area.
I've got some bad pictures, I should take some better ones.