We finally pushed our new intranet from development to production the other day. As I was checking the pages I noticed my theme was not showing up in the Themes list. Doh. Anything in the 12 hive that you added does not push when you go from dev to production. You have to manually move copies to all production servers. In my case, our farm has five production servers, and I have a custom theme, so thats three things I need to copy over to each server:
1: spthemes.xml
2: thumbnail image for theme preview
3: custom theme folder
Beyond that oversight, everything pulled over fine, all of my relative links work, pages are there, masterpage and page layouts pulled, all is good. ;0
SharePoint for Designers 