Maybe Scotland.

(Scotland is considering breaking away from the UK. We (I am English) have told the Scots that if they do that, they'll have to give up any influence they have over the pound Sterling. So that could leave them looking for a currency. They might go for the Euro (and might have to if they want to be part of the EU), but frankly the Euro hasn't looked very attractive over recent years. It would be fun if they went for a crypto-currency. I suspect they'd carry on using Sterling for a few years regardless and then switch, so Bitcoin would have some time to mature. They may not break away at all; they decide in September.)