Africa

and jonlubi, that would be so cool if you could ask your friends about that/ maybe give me an email address to get in touch with them. i haven't been able to find much about this type of ride online.

I'm not in touch any more with the one that actually dealt with Dawes, but the other guy says they did just call up and explain that they were doing the ride to raise money for a project in Tanzania building schools. They got 50% off two new rides!
I expect a lot of manufacturers would respond in a similar way - if you ARE doing the trip for charity that is, for which you would need to provide documentation/proof.
Could add a nice angle to the trip. You get to visit the people the money is helping, even hand deliver it.