Changing a bike's front end, wheels and rear damper is gonna cost you something, I can guarantee you that. Using high-quality spoked wheels for off-road use is even more expensive. And there's a bit of work to get them done as well. Sure anything is possible, and I will not be surprised to see such conversion done, but then it won't be such a budget bike any more.
Small fuel consumption is a very big plus no doubt. But it ain't the only one: for example the F650twin/800GS, or the newest DL650 will get very close to the consumption figures of this bike, the latter with a 20 liter tank (older version is not thirsty either, and its got 22 liters) so range with the stock tank isn't spectacular.