Hey Matt S -
If you can't find an obvious leak, it may be time to invest in one of those high-tech "virtual-rain spray-generators" that Monaco uses. To be more specific, I guess you could call it what it really is.... a garden-hose and spray nozzle duct-taped to a ladder and pointed at the seals.
That's what they used to find & fix my leaks, so I guess it works.
To answer your question about the slide-seals, I think you're on the right track; the tape will pull the seal-edge to the outside as it moves out and inwards as the slide is retracted. Imagine, if you will, that as the slide moves out, the seal is getting pulled/tripped/whatever such that it is grabbed by the slidewall and flips so's the edge of the seal is facing outward. Another way to look at it is to imagine yourself as a raindrop trying to get inside by sneaking past a slide-seal . If the seal is pointing outwards, it will minimize your ability to squeeze in around its edge, but if the seal was still pointed inwards, it would be fairly easy to do. Make sense or just confuse ya even more? (sure wish I knew how to post pics, definitely worth 1001 words here!). HTH.