Agreed - the idea of simply compiling & editing playlists (from a large Collection) on a popular portable device platforms for certain gigs would be super useful. (Obviously without the massive overhead of audio data, so playback/preview wouldn't be practical.)
Implementation suggestion: if the Export/Sync Management engine could be extended to include a skeletal edition of the Collection (like the Collection XML export), purely for the purposes of playlist prep, then use iOS/Android edition of RB to allow quick Collection search and add to playlists, then when resync'd to parent device, playlists are updated accordingly.