I had done
https://bitbucket.org/mpl/acme-with-easy-backwards-search , but since I wasn't bright enough to host it as a diff I don't really remember how it works or what I changed. I think I had added a Rev command to the tag bar of the window. Although it wasn't useful enough for me to keep on maintaining it, I'm pretty sure it was working.
Also there was a discussion on 9fans about it with other suggestions/solutions.