Early shots of Arne's frame - this is the split for the belt drive. Basically, I just drill the dropout for the M8 bolt, and bolt on the coupler (there are two sizes, this is the larger one, for oversized seatstays). It (along with the dropout) is stainless steel, so the interface does not get painted/powdercoated.
It's pretty simple, works well, and adds about 20g of weight. Nothing super exciting, but people ask me about this all the time, so I figured I'd post a picture or two of how I do it. For what it's worth, I'm still not a big fan of the belts for anything but townies - everyone I know who's tried one on a mountain bike has ended up back on a chain after dealing with constant skipping, popping, weird noises, and alignment nightmares.
This is an urban/CX setup, with SUPER beefy chainstays to minimize frame flex. In fact, the frame is going to be something of a tank - but it'll be fun to tool around town on, and hopefully the belt will work just fine for that.