Ferdinand bzw. sein Forenpartner scheint recht zu haben:http://www.worldwidewords.org/qa/qa-tem1.htm
(die Überschrift "...English from a British Viewpoint" kann ich leider nicht kopieren)
Q From Susan G McManus: Where does tempest in a teapot come from?
A I’m not familiar with that American version. If I wanted to express the same idea, I’d say it was a storm in a teacup, which is the common British equivalent. Either way, it’s a delightful phrase for a fuss about nothing very much, or a dispute of only minor or local importance.
These two forms are by no means the only ones. The big Oxford English Dictionary has examples of a storm in a cream bowl and a storm in a wash-hand basin, and suggests that there were others. All have this idea of a violent disturbance in a small compass, by implication therefore one of little significance. The alliteration of tempest in a teapot must have helped its acceptance.