All this Rapture nonsense annoys the crap out of me. I know, I know, it's no crazier than any other religious belief, but it's not in the Bible and it's not part of the Christian tradition, at least not until the 19th century. Rapturists are a whole 'nother religion as far as I'm concerned.
I was talking to my Dad, who studied theology in college and was meant to be a Campbellite preacher, about the Darbyites and where they got this foolishness from. His take is that they imagined that John, who wrote the Apocalypse, was more akin to Nostradamus than to a Biblical prophet. He was a fortuneteller, not a soothsayer, in their eyes. All the prophets, to such folks, were writing, not about the time and place they lived, but about the far distant future. How you'd know which prophets to include in your canon hasn't been explained, but that's how they see prophesy.
Dad reckons, and I agree with him, that John was writing in apocalyptic code about conditions in his own time and that he alludes to persons and nations acting at that time. He was regarded as a prophet because what he wrote was true when he wrote it, and readers at the time understood what he alluded to.
I don't expect Christ to return any time soon. As Martin Short remarked on Real Time the other day, he's probably going to visit the trillion other planets who didn't nail him to a cross before he comes back to us.