My wife's bike frame doesn't have any mounts for a water bottle so this thread interested me. I found a top cap cage mount from King Cage that I think I'm going to buy for her as a stocking stuffer. See it here, second product down, on the right side column:
http://www.kingcage.com/products-waterbottle-cages.html. I think this would be a little less distracting and possibly a bit safer, with the bottle held in a more horizontal position.
Edit - found a photo:
Some of their other products are interesting, too. Talk about a specialized niche product!