Are you looking into a Thorn bike?

Once you venture into Mexico south, for example, 26" wheel makes sense in general.The issue about availability of 700c and 29ers (at least in Mexico) is not in the larger cities where you'll be able to source these components, but in small cities and rural areas where 26" simply rules. Interestingly, I was recently speaking to the owner of the "boutique" bike shop in town. He said his clients don't want 26"-wheel MTBs anymore. They all want 29ers! Obviously, this doesn't reflect the reality of other places in Lat. Am., Asia or Africa where you might be interested in touring . 26" is the norm from all the blogs I've read.