Strange, "There are already eleven years" is refused. Warum? Es geht nicht!
I suggested "Has it already been eleven years?" and "It's already been eleven years?", because the suggested translation of "It's already eleven years?" didn't make sense to me. On second reading, I see that this could also be intended to suggest a counting of future time, so I'm thinking all of these possible English translations could be correct for "Es sind schon elf Jahre?"...
Yeah, it's a bit weird without context... Also that it's a 'leading question' - i.e. it doesn't have the word order of a question, but of a statement.