I'm not the expert here but I can tell you that burners are really not that expensive. If you go to the site listed below you will find a lot of information including prices, propane saftey issues etc. Marc Ward of Ward Burner Systems is a great guy and will be more than happy to return your e-mail questions or you can give him a call. He encourages people to call him to discuss specifics or general questions.
Harv, I'm looking at building a forge myself. Is that soft insulated firebrick on the inside of your forge? tia