I have definitely considered doing a metheglin with something from Teavana...I don't routinely add tannins to my mead except in certain circumstances, but it can be a valuable addition at times. I would think that many of the Teavana teas would have less tannins than your run-of-the-mill black tea (many of the Teavana teas I've tried use white or green tea as the base...)
Packaged: Dark Munich Citra SMaSH, Mayan Stout, Caramel Quad, Basic Spiced Cider, Spur of the Moment Graff
Recent Meads: Mead Day '11 Ginger Metheglin, Mead Day '12 Traditional (orange blossom) Mead, Fresh Simple Cyser '12, Cherry Melomel, Belgeglin, Bochet
Secondary: Why do I keep this line here...?
Bulk Aging: Cocobochet
Planned: Hop Metheglin #3 (NZ hops), Trad. Gesho T'ej