Magnus, is there any plan to deal with files that have multiple revisions? Two possibilities:
1) Save all the revisions to a randomized directory name (e.g. http://tools.wikimedia.de/~magnus/commons_images/ea6e6a5a74/) which is either listable with all the versions, or has an auto-generated index.html file that lists the versions
or
2) At least warn about this case, since currently the old versions aren't backed up.