Edit: This post was in reply to Ron's, not Flip's.
LOL... Considering that the original poster asked his question in 2006 and wanted to buy one that weekend I don't think any of us are addressing his question anymore.
If we are, he said he has a Defender which doesn't have much room... cot + pad seems like it is out on that criteria. He didn't specify what season, so an all season 2.5" pad seems more reasonable than a 1 season solution.
Craig