In the "Ben True is not Thin" thread his weight was discussed. True ran sub 4 when he was a skier-runner, weighing in the 160s. He's lost 15-20 lb over the past several years since he decided to focus on running instead of skiing.
As far as xc skiing being dirty, it's like this. At the professional/Olympic level there are dirty skiers. In the US, and NCAA level, the sport is so low key that drug use is pretty rare. In the past 30 years only one US athlete has been implicated in a doping scandal. That was Nordic combined athlete Kerry Lynch in 1987, who removed a pint of blood and had it re-administered several weeks or months later (old school blood doping, 70s style). They left a paper trail and some US ski team coaches turned them in after Lynch won a surprise Silver medal in the World Championships. As A Matter of Fact it was Ruff Patterson, who became True's college coach at Dartmouth, who turned them in.
Hate to insult but so many of you letsrunners are such idiots. I mean, really stupid.