Interesting. I've never seen this, or more likely never noticed it. A search reveals that some believe that it was originally spelled dilemna, which is ridiculous if you consider the etymology. Of some interest is the fact that the only dilemna one can find in OED is a citation-misspell (dating from 16th C.) under "horned syllogism". Well, that's certainly the horns of a dilemna.

EDIT: In Rhetoric, "a choice between favorable or attractive alternatives" is called a constructive dilemma; but I'm going to guess that's not exactly what you had in mind.

the Contrarian

the Contrarian