Just a note, I will accept just about any currency for buying art. I'm capable enough to find a way to transact in currencies other than USD. If you're British, we'll work in GBP. Europeans can use the Euro. Canadians are fine to talk in CAD.
However, I will never, ever, ever, ever, trade in any currency that is not backed by a national government (It's essentially worthless no matter what the yahoos claim about it) and fully fungible (that means transferable/replaceable). This means that I am not interested in doing business in any of the following:
Link
Orangebunny
Sweet, I can pay in biscuits?