Hi, Mike. Here is a link to all the Loudon Wainwright III information anybody would ever want. The song is on a 1993 Wainwright CD on the Virgin label called "Career Moves," which is a collection of a number of his more interesting songs. CDNOW.com lists only this and the Cash recording of the song, so it's likely there are no other recordings in general circulation.
He's written some good songs, but I can't say I like him as a performer. He's just a bit too crude and "in your face" for my taste. My kids like him, but I prefer gentler people.
-Joe Offer-