I was wondering about Domingo taking the lower part in that duet too. Since the role was originally written for baritone in French and Gluck tweaked it into tenor for the German version, maybe he just left as much of the baritone version untouched that fell within the tenor range. That's just a guess, though.

Just learned that this Saturday a Covent Garden version of Carmen is being shown at my usual opera movie theater...in 3D! At 3D prices, not opera prices.
http://www.carmen3d.com/?gclid=CKSViJfnq6cCFRtqgwodtmJDAw

It's being shown at other dates in other local theaters, so it's not scheduled like the Met's performances (because it's not live). Tony Hall, the Royal Opera CEO, said he got the idea to do Carmen in 3D when he took his daughter to see Avatar.