Theme URI in Theme download
When one customizes their own theme using the theme roller, downloads it, implements it, then later decides they want to make small changes to it, for example changing the icon color for default button state. That person is currently SOL, because even though they have a hard copy of the theme, they can't go back to the theme roller and say, "Remember that theme I was working on last week? I want that theme, but change the icon color."
The URI of the download page holds all the meta data required to generate the person's theme, so I suggest that inside the generated theme zip file, a file with that URI be stored. That way a person can take a downloaded theme back to the theme roller to manipulated it further and re-download it, without having the foresight to bookmark or otherwise save the download page's URI.
This could simply be the addition of a link in the index.html file. I've attached an example.