I'm moving this to be one subtask of the moodle 2.0 meta: backup & restore (MDL-21432)
Also, I'm assigning this to Sam, as far as I think we have one conflict here between the UI and the restore controller causing the moodle 1.x format not being detected (and informed) because the UI stuff gets executed before the controller checking of format.
This causes the restore process to "die" with "file not found message", where it should be "moodle 1.x format detected, still not possible to restore this" or so.
IMO we should try to instantiate the restore_controller earlier (before trying to get backup information and everything else), so the controller performs the format checks and end with status STATUS_REQUIRE_CONV or STATUS_SETTING_UI and format controller->get_format() containing the found format (imscc, moodle1...).
That way, the UI will be able (when implemented), to call controller->convert() in order to transform the backup into a moodle2 one. For now it just must show error msg and stop.
Any thought, Sam, can that be done in that way? First instantiate controller and look for status/format before loading info?