Will the coming year generally be pronounced "twenty-eleven"? Likely so (which, admittedly, is no different from what I speculated a year ago).
However, I think it might end up "twenty 'leven" because the last syllable of twenty and the first syllable of eleven are the same e sound, and thus we may almost inadvertently blur them together somewhat, because—of course—we've been having four-syllable years for the last decade, and five will seem just a bit too unwieldy.
I have a great amount of faith in our propensity for hints of laziness.
To say "two-thousand eleven" (all six syllables) will be how those who wish to seem erudite will do.
Happy Old Year's Day, gentle reader, no matter how what you plan to call next year. (Hurry up—you need to decide by tomorrow.)