This one has a data out, unfortunately you would have to drill the case to get the cable out! Aldi ones have a cover over the data out . The length of the scales would be the limiting factor IMHO, mounting accurately I don't think would be a problem as long as you can attach /make brackets.I was planning a similar thing myself, a home-made DRO to fit to the mini-mill. Most of the cheapy calipers have a serial data output you can decode with an Arduino or similar and drive a big display. Anothet project on the to-do list...
My biggest concern would be drilling and fitting the guts of the caliper to the machine accurately enough.