Delfi,
I think the biggest issue i have the pre-trib position.....is that so much of the passages purported to be "pre-trib" are taken completely out of context. Especially that no man knows the day or hour. If you re-read that passage in context, it is clear that Jesus doesn't even MENTION the rapture in that passage. The biggest issue i have is that the tribulation is only ever spoken of as being 3 1/2 years. The final week of prophecy is 7 years long...but the first part is the "beginning of sorrows". It isn't until the abomination of desolation that Jesus calls it GREAT TRIBULATION!
Still, i see room on this to go a couple of different directions. Depending on how one is reading certain scriptures. I used to use Isaiah 26 to defend a pre-trib position....but now i see it as simply being a rapture passage overall. Particularly as it relates to entering into his chambers.
It's also important to note that the rapture language in Daniel 12 occurs...and then the countdown to the 2nd coming is only 3 1/2 years. We're taking one passage in the bible...the prophecy of weeks, and turning that into the tribulation...when nowhere else is the entire final week called the tribulation.
This would be a fun study to do i suppose. Just to go through all of the passages for context...reveal the different theories, and depict the possibilities. I'm more than 75% mid-trib now....but i wouldn't bet the farm on it. It's one of the most complicated subjects...and without much to set us on a perfect union with scripture either. Those passages as to the timing itself are vague at best. I think God wanted it that way a little bit.