I've been trying to find one too. The CBS store used to offer one but no longer does. Perhaps if there is enough of a demand for them (though that's highly unlikely), it might return. I sent them an email voicing my request, perhaps you might want to do the same?
CBS Store - Help
I sent mine under the category "Product inquiry."
I would suggest to keep checking ebay periodically (that's where I first spotted one, but was outbid [I was jobless at the time!]). Maybe one day we will get into a bidding war with each other.
Ralph Malph 
