So is having a once piece machine preferable here to something like the Acer Nevo + a separate display ?
For touchscreens, given this is a one off you may want to look towards either surplus EPOS equipment (although size there could be an issue) or displays from surplus pub style quiz machines (which tend to be PC based inside anyway) as a source for the screen...the latter of course will be an internal screen module which would require effort to wallmount/enclose
Most touchscreens I have dealt with tend to behave as a standard mouse with either right click events dealt with in hardware or software as a touch and hold....although I am guessing for this application you could escape the need for right click anyway.