There might be other ways around the problem. In my community any detached building that will be used to store a vehicle is called a detached garage and the exterior must match the house. Since the houses are brick, detached garages must be brick as well.
Many of my neighbors put up large metal buildings and workshops that aren't brick faced. They just told the city when they pulled the permit that they weren't building it to store a vehicle. Of course once finished they changed their minds and parked their vehicles inside, which strangely enough isn't a code violation.
My immediate next door neighbor and I both build detached buildings that contain vehicle storage space, in my case an RV, and a workshop. Not knowing how to play the game with the city at the time, we honestly told them up front what we were going to put in the buildings, so we have large brick outhouses in our backyards.