Hi! New guy on this forum, considering to get the Birdy Touring. The specification for the current model says it has a 9-32t 10-speed Sunrace cassette, one I haven't been able to find on the Sunrace website. Do you know anything about this? Does it mean the hub uses an XD driver body?

If so, that would make it compatible with standard SRAM 10-42t 11-speed cassettes, and even the e*thirteen 9-46t. That 9-46t is expensive, but would be exactly the gearing range I want. Such a gigantic cassette would look funny on the small wheel, but more importantly, do you think it would even work? I'm worried about the chain rubbing the frame.

The alternative would be adding a front double, or building a new rear wheel around the SRAM or Sturmey Archer dualdrive hubs. Yes, the Rohloff has the range, but it's expensive, heavy, and hard to get fixed on a tour, if something happens. The safest bet is a pure derailer gear setup.