well, I can't edit my own post anymore, but just to add:
1. make a new playlist on the pc.
2. open the existing playlists.
3. drag these items to the new playlist
4. accept that there might be duplicates and confirm that I do want copies.
5. do this for all the playlists.
6. plug in nano
7. tick the new playlist (all my music is synched by playlist only, I do not use ticked songs etc. all the music is already on the nano inside the original playlists anyway).
8. hit sync.
9. unplug nano.
10. press music button and open the playlists item
well, my new playlist containing what should be all that music I just put in it WILL NOT APPEAR. I've sync'd 3 times now. It says it's done. It shows it's ticked.
So there's no way to queue multiple playlists.
Can someone help me out? I realise that Apple staff do not frequent these forums or reality very often, so perhaps a community member knows the trick?