 I think that we are all agreed that citations should be specific to the 27 club, so I think that can be put asside. With regards the quality of ciations, I don't think the 27 club websites meet WP:RS, as they don't seem to have any professional editorial control, but are rather run by fans seeking to put up as much content as they can, and therefore shouldn't be used to support this article. However, taking on board Mudwaters line on primary sources from before, I think a formally published book on the subject is an acceptable source. Checking the primary source policy I think it doesn't exclude those books and in pretty much any other subject a published book is accepted as a source, so I think it would be peculiar to say differently here. That would leave us with normal third party citations (web or otherwise) and the 27 club published books. I think that given the inherant notabillity of those sources, the issue of having a wikipedia page becomes moot. If you are notable enough to have third party sources link you, or for someone to put you in a published book linking you to the club, odds are you are notable enough to have a wiki page even if it hasn't actually been created yet (those same sources would likely support such an article). If the odd marginal person creeps in that way, c'est la vie, no system is going to be perfect.     