If you don't have a mold to make the part in, gelkote can be sprayed onto the finished part and then wet sanded with 200-400-600-100 grit papers and then polished with rubbing compounds. We do this all the time in our boat yard to make repairs to gelkoted parts.

Getting the gelkote to work over epoxy however can be pretty challanging. It will often not cure. If you want to try gelkote, you might consider putting down a layer of polyester resin first. For some reason, polyester resin seems to cure over epoxy OK but gelkote does not. Regardless, I think it is a pretty dicey deal if you are using epoxy over wood. This is probably why no one else is doing it.

Craig