I can see the duplicated comments right in the Blogger export (xml) file so naturally they appear when I convert to a WordPress file. This being the case I don’t think it has anything to do with the theme.

The problem seems to appear in posts older than 4 or 5 months. The most recent posts are fine.

You can view an example here (blog not live):
http://vps3204.inmotionhosting.com/~wootdog/2008/12/ready/

And here’s the original Blogger post:
http://www.wootube.net/2008/12/ready.html

I would cut/past the same from the original Blogger export but I’m sure you can take my word for it that it’s there.

There’s an ongoing support thread in the Blogger help forums.

I’m going to sneak over to fussy.org and see if I can find any duplicate comments in her archives 😉