Hi Lyle,
I just saw this issue (sorry – not always easy to find the most updated one initially). I'm also trying to allow Free Shipping on a specific product. I found a possible solution at this post, then submitted a reply because I still have an issue that sounds similar to this thread (that's why I'm posting a link here – trying to to double-post issues).

Can I ask you to take a look?

http://www.ubercart.org/forum/ideas_and_suggestions/482/free_shipping_th...

Thanks for any advice!

Cheers–
Scott