Jon Muir (Australian). He has climbed everest a couple of times (without oxygen and up new routes. I think he also did it without sherpas once). Has also walked unassisted to both poles, has kayaked solo up the east coast of Australia, and has walked, unaided, living off the land (mostly) with cart, across Australia (~2000km, ~120days) and also to the geographic centre of Aus, in different trips. Bear in mind, once you get about 200km (give or take) from the coast of Australia, you are pretty much in full-on Desert...
I'd like to hear his thoughts on going more UL. He has his gear list from his across Aus walk listed in the back of his book, and its nowhere near even LW. Sure, he took camera gear, an EPIRB, rifles, and a cart to drag it all in plus 45kg of rations, but most of his gear could have been a fair bit lighter.
Jon, if you ever google your name, maybe you could respond here? I wonder what you could do if you replaced half your gear weight with more carbohydrates...Also, what do you think someone-anyone-could do with the right training, fitness, gear, age... (I'm poking about W-E across Aus here).