I am putting together a Bitcoin only web advertising co-operative that accepts ONLY Bitcoin. While it may be detrimental in the short-term to accept only Bitcoin, it will be a business decision that more and more businesses will ultimately face as their sales with Bitcoin grows and and those with credit cards shrink.
Web advertising is a different beast when you consider that any site that is buying it (i.e. our customers) can also install our free API and become a member/web traffic producer and seller of it (and earn Bitcoin in the process).
And for those businesses that start accepting Bitcoin themselves (like those the OP is building a list of) it gives them a place to spend it for legitimate business expense and avoid having to convert it to fiat.
I have seen some companies accepting BTC only and then ending up being forced to accept fiat again because it's unfortunately still way too early to deal with BTC payments only it seems.