I went out shopping for something else the other day with my R-D1 in hand ready to go elsewhere and take some pictures. It felt wrong holding it and i didn't want to put it round my neck so whilst i was out i took a quick look at camera bags available in a few smaller shops.
Having the R-D1 to hand i was able to see which ones fitted or not. I already have a crumpler bens pizza XL bag for my canon SLR, which is quite stealthy and can fit a few things in. I was keen for some basic protection and as small as possible. In the end i spotted the Edit 110.. its actually described as a mini dv camera bag, its not THAT stealthy being Lowepro but its very very small. Actually testing it with the R-D1 and I noticed that the interior space of the bag was the same size as the R-D1 itself.. it fits in on its bag nicely snug against the soft walls. The VL 35mm ultron lens is close to the top of the bag, I have no other lenses so i cannot say whether they'd fit or not. Beyond that you can fit plenty of caps, and cards etc.. at a push you could perhaps fit a smaller lens in the bag with the camera.. the lens wrapped in a small layer of bubble wrap would stop it doing any damage to the camera and the whole package would be nice and small.
My rationale was that inside this bag its nicely protected with a reasonable amount of foam.. its also nice and securely fitting exactly the space available so it wouldn't move around at all. Combining it with a backpack could give a more long term solution, along with then looking exactly like any one else with a standard bag. In fact anticipating having to send some packages recently i brought a load of bubblewrap home in bag i take to work. I've since left it in out of lazyness but have noticed how its added a lot of protection to the things that i take in.. I believe this Edit 110 bag with some bubble wrap and some clothes would sit very securely inside a standard rucksack, giving you a very safe home for your camera whilst remaining quite incospicuous.
Its not ideal in fitting multiple lenses, its also not that quick to get into, you have to unzip the entire main lid after releasing the velcro strap.
Still just thought i'd point it out purely for the fact that its tiny, and it fits the R-D1 perfectly.
I've uploaded a few pictures of it and my camera (including a few shots with my crumpler bag to give you a nice idea how much smaller it is than that bag) here
the bag itself is on lowepro's site here