About 12-13 years ago, a toasted coconut porter took the NHC. I'll see if I can find out what category it was. Maybe Gordon would know.
I judged Fujiura-san's mild (twice including BOS, where it won) this summer in Japan. Really good damn mild. I looked online and the same recipe shows up everywhere including on the green board where someone pasted verbatim text from an email, so it seems legit. He is legendary in Japan for this beer. Apparently he got a bit of a hand slap when Zymurgy published that he won (homebrewing is not legal in Japan if the alcohol is greater than 1%, it is pretty well decriminalized though).
Back to the point. I would argue under the 1998 guidelines that coconut beers should go in fruit beer. It would be interesting to know where this was entered.
Under the 2008 guidelines, the SHV category specifically says nut based beers go there. I think that is vague, but I know Gordon believes (because he said so on the BJCP board) that should include coconut so I believe that was the intent. The coconut question comes up A LOT and I think it would be a good idea to clarify in the next revision.