So, I mentioned my little project to my boss...and he donated to the cause

Roland Plotter - Imgur

Couldn't find the power supply, so had a bit of a faff about getting 9v and 31v in there, but got there in the end.

Going to see what my options are with it before I spend a load of money, though I'm only mildly hopeful that it's suitable for the job. We'll see...