A couple seat sources

[RDFL]

https://www.tuffside.com/  ----  https://www.mactops.com/motorcycle-seats-seattle.php

[pdxjim]

Ginger is a friend of mine, and the best in the biz:  https://www.newchurchmoto.com/

[IR8D8R]

Anybody know a custom MC seat shop in the Southeastern U.S. to recommend?

All the ones listed so far are on the West coast. I am in East Tennessee.

IR8D8R

[RDFL]

A upholstery shop near you can do it, ask motorcycle shops near you for who they use.