Is there a good cover that you could use? They are portable, don't take up much room, and relatively inexpensive. Trailers can be easily stolen, canopies aren't designed for long term use, and a shed would be expensive.
Also, ST's are taller than most people think. I rented a trailer to bring mine back home (thank goodness, we hit a bad ice storm coming back) and getting it in, getting off, and getting out wasn't easy. Plus opening/closing/locking/unlocking every time would be a pain. The mini tent garages are a good solution, but I don't think the manager wants you to get a permanent parking spot (even when you are out riding) and he probably wouldn't like you doing holes for anchors.