Thanks for all the help so far...I emailed BMI again today, but so far I haven't heard anything from them.
I guess I will try and contact Nanci Griffith's folks (I love her music) and see if they could ever look it up in their files.
Michael Burton, apparently is/was a lawyer in LA and has written other songs, but this was his only cowboy song. I had heard that before, and Nanci Griffith mentions it in her album notes.
I had heard that this an elusive song to track down..and I guess that is true. Again, if anyone knows of anyone who recorded it (with permission) and can contact them to find out what they know, I would be very grateful. I really want to do this right...