I'm 6'1" and I weigh about 165 lbs and have long legs...typically wear pants with inseam of 35-36".  In all my life I have never had a pair of long johns that fit in the waist AND came all the way down to my ankles...always been aggravated by the clothing industry's assumption that if you're tall, you're also big!  I saw a reviewer here who's height was 6'3" and seemed to have a similar build who said the large had enough length, so I decided to give them a try.  They fit PERFECTLY!!  Even after washing!!  WOOHOO!!  Our ski day got rained out last week, so I don't know how they'll perform as far as keeping me warm, but I'm so excited they fit, I'm not too worried about that!  Besides, it doesn't usually get that cold here in Virginia.