Well not really. A regular riding buddy of mine used to ride with guy before he moved who did the Tour Divide a few years ago. The guy was somewhere in the southern third of the race when he blacked out from exhaustion and dehydration. He woke up in the hospital with another guy from the race in the bed next to him. So yeah these guys do push themselves to unsafe ends.

First thought, do a search on "ultralight" on the Touring board and you will find a multitude of good threads. Folks like nun and bekologist have provided great information on ultralight touring.

Second thought, there seems to be two points to your comments, 1) ultralight set ups (both bike and gear) and 2) long distances in the day. Yes ultralight loads will make putting in lots of miles in a day easier but ones fitness and ability is equally or more important. This second factor is hard for anyone to ascertain via a web forum. Ones set up is something that we can all understand as the weight of a bike, tent, etc. is what it is where ones fitness is relative. I guess the point is 50, 100, or 150 miles in a day is such a personal thing.