I just picked up a pair of these magnetic salt and pepper shakers:
I think they’ll be great to keep on the table in the Airstream. And hey–half the footprint is always a bonus! (Made of beech wood with embedded magnets to help attract them to one another, $35.)
Also, a while back I purchased this little concrete salt and pepper cellar for the Airstream and it fits perfectly between the stove and the magnetic spice wall.