This CNNMoney article
has an interesting review of the Swiss currency:
The Swiss franc, one of the world's strongest currencies, has been on a tear in recent months, and is now flirting with a new all time high against the U.S. dollar.
offers CDs and money market accounts held in Swiss francs, but the accounts currently don't pay any interest.
I would be a little nervous to put too much into the currency of any small country. Many EverBank customers who invested in the Iceland currency accounts had big losses in 2008
when Iceland experienced its financial crisis.