As far as I have been able to find, only company making production side pipes these days is Patriot. I too would love to have some variety in our choice of pipes, but the market doesn't seem to be there for it these days. Thorley and Thrush used to make several. I'm planning on having a custom set built when the time comes for the Queen Anne's Revenge.
Learn something new every day. Did a little online reading during my last coffee break and it appears Patriot exhaust and Thorley are one in the same now. Apparently Doug started "Headers by Doug" by Doug in the late 50s, eventually it changed to "Doug Thorley", then after a divorce where his wife gained the business, he started "Doug's Headers" which was bought out by Pertronix in 2005. So in a long round about way, they're what has evolved of the old company now. Attached image snatched from the Pertronix website.