These 2 links explain why biomechanically people with long femurs in relation to their torso have trouble squatting and deadlifting using the generally accepted range of motion for these lifts. These people are limited by their proportions and also these same proportions make them more easily injured as their leverage is severely compromised as compared to a person with more “normal” length femurs .
But all is not lost, even with this disadvantage one can get tremendously strong by just doing partial movements of Squats and deadlifts from different heights. One must experiment with stance and varying ranges of motion. These lifts are still the absolute best way to overall body strength and power.
note: I checked these links and apparently they don’t work anymore, it just goes to Yahoo.com
So, check this link out (especially pay attention to the part when he talks about longer femurs than torso , this is the group that has the issues, long femurs in proportion to the rest of the body are not the problem.)