Sorry for the late response! Short answer: I actually have no idea.
Long answer: I credited them via Pokéfarm Q username, and it looks like they either changed it or deleted their account since then. (The comm was at minimum four years ago but more likely 4-5+ years, and I had a long stretch of inactivity on PFQ before just coming back recently, to give you an idea.) To the best of my knowledge, their trade shop no longer exists (makes sense as the site deletes threads after several months of inactivity), and I have no PMs from them because we communicated through the shop. I even looked to see what art shops still exist from that time period, in case they're still running it under a changed username, but no dice.
However! In that process I did find a couple shops that do that kind of thing, specifically edits of existing trainer sprites as mine was:
I haven't used them personally, so I can't speak to things like prices or commission turnaround. However, going off of the examples, it looks like these people do good work!
(Apologies for not being able to solve the mystery, though...)