The 2x2 brick can be generated based on the information in the datablock alone, it doesn't need a brick file.
Well...
I took a screenshot of a 1x2 brick wall and placed the brick texture on it.
As you see (marked with black stripes) it is not possible to get those bevels as they are on the brick, atleast not with one face, because they're wider than on the texture itself. How is this done?