There's no question that Apple caters to the high end/premium market, but this is outright esoteric. I'm skeptical that something like this can sell any more than the iPhone 5C.
At 27" it's not too far off of the DPI of the rMBPs. On the other hand you're probably sitting farther away from a 27" screen than a 13-15" screen, so lower a lower DPI might be more reasonable.