Anybody put together a 700C bike with a Roloff hub and couplers? Seems like a good touring bike. Perhaps a TI frame also.

That particular configuration would appeal to a few project builders, I think, but your design is for a travel bike (couplers, vs. folding). If you will be decoupling and recoupling the frame, and have the RD ground clearance of an ISO 622 wheel, I would go with an RD and avoid the "uh-oh, the hub has self-destructed" risk, and have an entire high-end bike for the cost of the Rohloff alone.