Even before purchasing the CB1100, I was scratching my head searching for bike specific accessories. Guth mentioned Samurider in a thread, and since then several folks including myself have ordered seats from the owner, Takashi Takase. Takashi is very easy to work with, and he promptly answers all your questions in excellent English.
Honda's Japanese accessories brochure lists a chrome chain cover from PLOT. The cover is not listed in Samurider's website, but when I asked him about it, Takashi ordered one for me and is sending it out in 3 days. Shipping will be another 3-4 days. I'm paying 600 yen less than what it's listed for in the brochure, plus about $22 for shipping.
I suspect Takashi can order just about anything from the Honda catalog or any other accessories manufacturer in Japan. So while shipping may still be expensive on some items, US riders can customize their bikes more easily through Samurider than when dealing with some other Japanese firms.
http://www.samurider.com/?cat=98