Per bug 1063215, we are going to be very soon creating about:home snippets that have the ability to install themes. We've done this in previously years, but we haven't done it lately. We know users that customize Firefox, use Firefox more, and thus these snippets are important for retention. We need an HTML page on AMO that includes previews of the themes that can be moused over and installed in one click. The UX should be very similar to browsing themes on AMO. Since the previews will have to be on AMO, more content will have to be on the AMO HTML compared to the add-on snippet in bug 1063170. We have a developer that can do this coding will do a pull request to be reviewed and merged by the AMO team. This is a P1 and Chris Beard would like to see this launch as soon as possible.
Apparently cbeard didn't want this _that_ bad, or this got implemented in some other bug. :P Either way, this looks abandoned to me. Closing!