Thanks for the comments – wood is an option i hadn't really considered, and may be feasible in the valleys, but don't think it will work higher up – no vegetation. Still, I have read some interesting articles on here about the BushBuddy, so may have to give that some serious thought.
Previous experience in the Himalaya and Karakoram suggests that kerosene is available almost everywhere – a big advantage. I've always used an MSR Whisperlite for this, which works fine but is heavy. I guess the XGK is the really bomber multi-fuel stove, though.
I saw a comment on an earlier thread about the 'stans that suggested that gas canisters may be available in some places. I was interested, because I think this would be a lighter option. However, I've also heard tales of gas canisters being (partially) refilled with water in South America – not something I want to find out 3 days into a 2 week trip.