Seems as though the Light Delight to be created by 300 Crumpler precisely for this task! Cross put there (handle upwards) is my camera always ready to hand. The zipper top running - perhaps a bit unusual - back to the tray, the opening is large enough to comfortably stow the camera and a spare memory card and battery pack in it. The outer material is to save weight - and for the Light-Delight-series has been so designed - relatively thin, inside the bag, however, is well padded. If you want, the bag can also carry on your belt, for all other offers of the shoulder without sufficient additional cushioning comfort.
Total (camera, lens, bag) weighs less than 700 grams of the combination - so who wants to establish the possibly lightest DSLR equipment in the world, who can not get around this bag. It should be noted of course, is that other than the 100D should fit any other SLR camera as inside.