Not sure which fixtures you have, but if they're flourescent and the bluish tint isn't appealing, many lighting specialty shops now carry miniature fourescent tubes in "warm white" tones, that are much more natural looking than standard mini-tubes... Worth considering if you keep fixture with new covers.
Local hardware store also carries extensive line of Chinese-made brushed aluminum low voltage halogen surface lights intended for under-cabinet installation in homes, but could be adapted to Airstreams in 1 or 3 or 5 lampt units by bypassing the 110V to
12V internal power supplies...