Some of the Six Flags parks have edited the trains on their Batman B&M Inverters so they now run backwards and will be turned back around at the end of the season. I'm not sure if its something that Alton Towers would actually do but it does seem quite interesting.
I think many people have said this before I have, but it would be cool maybe if they just changed the back row on each and (somehow) added in a backwards riding queue, similar to a front-row queue. Would add a small feature.
And then some of these theming experts TTF is full of could come up with a story as to how some of it ended up backwards