Neets is not stocking an on-wall mount for its 4" Touch Panel, but we have found a model which is suited for the job.
It is a Leviton 42777-1EB Surface Mount Backbox, Single Gang, Black, 1.45"
Aesthetically we would prefer you used a standard in-wall, but know that it is not always possible, that is why we've found this solution for you!
It can be bought here on Amazon or found in some US hardware stores as well.