I have a Sony RX100. I got a Tamrac 3821 bag for it. Camera fits perfectly but the bag has a fixed belt loop, which broke after a few weeks. The fixed loop is hard to remove (have to undo my belt), so I kept it on even when I was putting pressure on the loop by sitting in a chair.
Next choice was Tamrac 5686 which has a velcro loop but is a little small for the camera. It's easy to get the bag on and off but I'm putting pressure on the camera sliding it in and out.
I didn't see an obvious right choice on Tamrac's web site. I think the other bags that are in the same size class as the 3821 also have a fixed belt loop.
What do I want that holds an RX100 but has a velcro belt loop instead of a fixed loop?
I use a Lowepro Apex 20AW with my RX100. It has a velcro belt loop and a rain cover. It is snug - my RX100 has the Franiec grip on it and there is really only enough room left over for one extra battery, but that is exactly what I wanted, a bag to protect the camera that doesn't take up any more space than necessary.
I use an OP/TECH Digital D-Compact soft pouch for my RX100. The main pocket has about 1 cm spare on the side and top, and the depth is just right. The front pocket has room for a MagFilter CPL, a spare battery, and a couple of cards.
I use a Lowepro Dashpoint 10 - well-padded, and a snug fit for the camera alone - I like compact bags to be as, well, compact as possible. One good thing about the bag is that it is 2 options for belt loops (i.e. horizontal or vertical), both velcro.
I have an older Crumpler neoprene case that fits the RX100 perfectly with the grip. No room for anything extra though. Pretty sure they don't make it anymore.
That Dashpoint 10 looks pretty good -- I noticed that B&H has an Item Demo video: http://bhpho.to/X0qWuG
I don't need room for accessories in the belt bag. For example, my plan is to keep the RX100 on my belt when hiking and put a DSLR and supplies in my backpack. My plan last year was to keep a larger camera on a belt but the belt mounts I tried were not reliable.
