I think there is one shop in Maple Ridge that would order the parts for a conversion but likely you would be left to your own devices when it comes to installation and set up. I had inquired about that same type of conversion but had little success. Most shops have never heard of those hubs.
Trek 520 total custom build, Cannondale Mountain Tandem, Oryx Mountain Bike
Last year I researched doing the same thing to a 520. Dropped the idea. No one knows anything about the Rohloff hub. (Talking bike shops in my area) Seamed like a cool idea at the time. In Vancouver I do not know of anyone. Now, there is a shop in Tolfield, Alberta, Arvon Cycles. He makes custom bicycles, and can alter yours as well. I mailed him my frame. He cut the brand new 520 frame and added S&S couplers. Why am I telling you this? You realize that you will have to have the frame cut and a coupler of some sort put in, to allow you to install the belt. Once that is (pick whichever is appropriate) brazed, welded, soldered in, you will have to repaint at least that chain stay. I decided I didn't like the bronze color of my frame, so I sandblasted, primed and painted the bike. Complete with painted logo work. Do not tell your wife how much this stuff costs! hahahaha
I wasn't able to find any shop in the Vancouver area that would do this. The closest bike shop I could find was Cycle Monkey in Albany, California. They claim to be the sole North American Service Partner for Rohloff. They quoted me a price that would have more than doubled the price of my Trek 520. Somewhere in the $2000 range. They did not mention S&S couplers, so I assume they did not have to be added for a chain set up. I have since decided that my present set up is fine.