I use the Clip-Draw a lot, in such circumstances. I can carry my XD45 comfortably, sitting or standing, or quickly remove it or replace it. The XD series is particularly well suited to this type of holster-less carry, because the grip safety makes it unlikely that any sort of obstruction that might possibly make its way inside the trigger guard could cause a negligent discharge.
I have been carrying this way for about 3 years, and it is my favorite and most comfortable way to carry. If I need to remove it, I simply slip it out and into my Maxpedition FatBoy, and then replace it easily in my waistband, when appropriate.
http://www.clipdraw.com/store/index.php ... how_detail
