I've never heard of a dark and stormy. It sounds great. What is the ratio? Is it just ginger beer and dark rum?
Does it change things up a bit?
Bunderburg rum make a Dark and Stormy pre-mixed in a can.
1 part dark rum (traditionally Gosling's Black Seal) to 3 parts Ginger Beer (Ginger Ale is not a good substitute). I usually add the juice from half a squeezed lime.