I use the Billington Hadley (small) bag for my R1s which has been a great solution and I can take some accessories, filters etc. and still have a very compact and lightweight way to carry everything.
The clasps of the Hadley open quickly and silently and the inserts can position the R1 ready for you to grab instantly.
After five years of toting it around the UK and Europe, the bag still looks new and never shouts 'camera', so you can be discreet.
As for a successor to the R1, there is nothing on the horizon in terms of fixed-lens models but the NEX series look to be the way things are going. As Sony broaden their range of lenses, the NEX7 has to be where the R1 owner should be looking.
Examining shots taken by Digital Camera Resource with both cameras at the same location, the NEX7 delivers images with very similar qualities though with far higher resolution, which is a real credit to the basic quality of the R1. I think the R1 can see me through a few more seasons yet.