+1 on the Topeak " compact handle bar bag ". I used it with the "cross brakes" that are mounted on the top of the bars with out interference. The brakes are a rotated down to a natural 45 degree angle . The quick release mount is over the top of the cables. This causes the mount to be canted slightly upward (reccomended in the installation instructions) resulting in a level bag.
Thie "bar bag" version uses the same quick release mount and claims to be more water resistant than the "compact handlebar bag"
http://www.topeak.com/products/Bags/BarPack