Hey, now I don't feel so bad about my reactions to the unusual!
I do believe Wally's gold Airstream was annodized (as Katt suggested) and that's why it has held up well over the years. Avion used to use annodized aluminum for their trailers and most of them can be cleaned-up to look pretty nice, still today. Over the years, I have wondered why Airstream doesn't go this route. It would give a bit different appearance to the trailer (while still keeping it recognizable as an Airstream), but the payoff would come years down the line when they still looked good without the failing clearcoat/plasticoat.
So, putting together several ideas expressed in this thread: I could certainly see a pink, annodized finish Airstream (with maybe a bit of tasteful pinstriping) behind th Nomad. OH YEAH!