I don't think there is an answer for this. I decided to look up the top 25 RB's in terms of career yardage. Granted, they played during different eras, but here are some facts about the all-time top 25 list (stats gathered from
http://www.pro-football-reference.com/):
- None of the top 4 were over 6'0"
- None of the top 4 were over 210lbs
- Avg size of the top 4 is 5'9.5"/204.25lbs, with none of them off this target by more than 1.5" or 4.25lbs
- Only 3 of the top 10 were over 6'0"
- Only 2 of the top 10 were over 220lbs
- 4 of the top 25 were under 200lbs
- None of the top 25 are under 5'8" or over 6'3"
Top 25 by height
6'3" - 2
6'2" - 5
6'1" - 3
6'0" - 3
5'11" - 4
5'10" - 5
5'9" - 1
5'8" - 2
Twenty of the top 25 were between 5'10" and 6'2". I was surprised that the number over 6'0" was as high as it was. Avg height is 5'11.75"
Top 25 by weight
240lbs and over - 2
236-240lbs - 0
231-235lbs - 3
226-230lbs - 2
221-225lbs - 1
216-220lbs - 6
211-215lbs - 1
206-210lbs - 4
201-205lbs - 1
200lbs and under - 5
Seems like the weight is more distributed than the height. 10 are 210lbs and under, 8 are 211-225lbs, and 7 are over 225lbs. Avg weight is 215.3lbs.