You might like to try this one...I have the Ortlieb medium size and it fits well between my shifters, cables and handlebars. I have a bracket on my road bike (it isn't very big) and it was well worth the money for the second bracket which is on my touring bike. Sometimes just having a bag for snacks, camera, extra clothes on a long day (for layering, etc) is really nice. It easily moves to my touring or road bike. It is ABSOLUTELY waterproof and I have ridden with it in LOTS of rain. Yes, a little pricey, but my husband is in his 6th year with his (with thousands of miles on it) and all it has done is fade a bit...he got red. I have black and it is great! It comes with a strap so if you leave the bike, you can carry it like a purse, albeit a large one!!! The bag locks to the bracket but that is sort of ridiculous, as the bag unsnaps to open!! I never use the lock.

http://www.thetouringstore.com/ORTLI...205%20PAGE.htm