Keeping the camera in the front is the best way I have figured out. Once you get to that point you will likely be choosing from the variety of handlbar bags availible. I ended up liking the Hobo style of bags and stuff smaller canera bags into it:
GF1 with 14-45 and case inside my Acorn bag by
rperks1, on Flickr
The next hurdle you will face is the self realization of how big and heavy the conventional DSLR gear is. This has led me down the path of the micro 4 3 format over the last year and a half. I am getting the results and flexibility of the DSLR format with half or less of the package size. I still have my canon and some of the kit has sentemental value, otherwise I would have sold it by now.
Once you have gone that far you may start to look at you needs and a camera like the Panasonic DMC-LX5 and notice that it will meet 90% of you needs and is barely bigger than a pack of note cards. Even with a camera that small I would still be keeping it in the pocket of the Hobo bag.