As to the concern over the rohloff I read Thorns site and it emphasized that steel is best because it can be repaired anywhere in the world from a modern town to an outback village that's the reason I've excluded the rohloff, it can't be fixed anywhere but the conventional gears can. I've no doubt the rohloff is an excellent piece of kit but cost and world wide resources rule it out for me
Your logic about the Rohloff vs. derailleurs is not quite right.
First off you have to compare the likelihood of needing to repair a derailleur drive train vs. the need to repair a Rohloff hub. Having toured with both and done lots of research about how Rohloffs can fail and how many fail I can say that the advantage goes to the Rohloff by a landslide.
Second you have to consider how likely is it that you are going to get spare derailleur parts anywhere in the world as you suggest above? Certainly in any reasonably sized first world city you would. But if you tour in the more remote spots of North America or Europe there are no full service bike shops to provide you with an XT derailleur when you rip yours off. If you start looking at Africa, India, remote parts of South America spare parts are not abundant. The more remote and far flung your bike tour the more likely you'll find no bike parts available at all. That certainly favours components that are very unlikely to fail rather than ones that fail a lot more often.
The other thing to consider is a lot of the places that have ready access to derailleur parts, such as moderate sized first world cities, also have access to international courier services so in the unlikely event you need something for your Rohloff a phone call and a day or two in a campground/motel will see it in your hands.
Having said all that I don't think Rohloff is the perfect answer for everyone or every tour. I own and use derailleur bikes as well as Shimano IGH bikes and a couple Rohloff rigs. There are pros and cons to each option.
I don't like touring in populated areas with lots of cities and my favourite tours are in remote areas - deserts, mountainous areas that have little to no services. So I'd much rather use a Rohloff that is very reliable than a derailleur drivetrain which has a lot of vulnerabilities because when I do rip my derailleur off there will be no place to get one from.
I should also point out that the Rohloff has three other really important benefits for the adventurous tourist:
1 - nearly immune to weather. I've ridden a Rohloff bike for days on dirt roads in the pouring rain with the drivetrain literally caked in mud. The difference between how it shifted and pedaled between day1 when it was clean and day 5 was zero - I literally couldn't tell the difference and I was too beat up at the end of each day to do any maintenance. Riding derailleur bikes in similar conditions I haven't gone 2hrs before they stopped shifting properly and I had to either try and clean them or just give up on some gears until I did some maintenance.
2 - because you aren't shifting the chain on a Rohloff you can get so much more mileage out of one before you need to do anything. And then you can turn the whole drivetrain around and wear it out in the other direction before replacing everything. So even if nothing breaks the maintenance cycle for a Rohloff is so much less than a derailleur drivetrain. If you are riding from Alaska to Ushuaia through lots of remote spots that's very important.
3 - the dishless rear Rohloff wheel is much stronger than a dished wheel and easier to maintain because spoke tension is equal. That solves one of the big problems of a deraileur touring bike where building a robust dished wheel is a problem. This is especially true if you are riding off paved roads where the abuse a heavily loaded rear wheel takes is 100 times worse.
safe riding,
Vik
www.thelazyrando.com