Hi & welcome to the board. I'm a bit confused. You say you tracked down the maker of the quilt & the designer of the pattern, but you don't know the name?
To be honest, it looks like a pieced quilt back where they used left over pieces from a quilt.
It should be easy to duplicate. The strips look pieced with random sized patches. Decide on the width of the narrow pieced strip (probably 2 or 3 inches). The strip on the right looks to be 3X the narrow strip (so 6 or 9") and the wide center strip is 4X (8 or 12) the background strips separating the 3 pieced columns are the same width as the narrow pieced band. Add strips of the background fabric to make it the width you want.