Anyone with a CNC machine could cut out a pickguard for you.
Only thing is you'd need to give him an exact tracing in vector format.
That's what I've been doing for customers who want a vintage correct pickguard with Tbird logo.
A one off custom pickguard might be costly as getting the vector file into the CNC programme is a labor-intensive job.
Once that is done, it doesn't matter how many pieces you make. The it's down to the material costst. And finding the right material of course. I have yet to find a source for the right thickness of vintage Gibsons, as all the standard three ply pickguard material is a little too thick... (not that anyone will notice once it's mounted)