Of the basic football training exercises (squat, bench and cleans), the power clean transfers over the best into useable quickness, balance and strength for players, in any position. Add and push press/jerk to the cleans and you really have an all around training football movement.
Any lineman (for example) should not forget to focus on half squats (leg drive, most of the time, starts from a half crouch). Half/quarter, to top lockout, presses for benches. Half/quarter cleans for pulls. Though a full ROM should be included in any training workout. Quite a few torn tricep and biceps in football. Short range violent arm involvement is used heavily in blocking and tackling. One of the reasons that short and powerful ROM's should be encouraged, with pushing and pulling.
From my experience (take it for what it may be worth..I am not all that) the Combines are ego stroking for the owners and coaching staff of any NFL team. Everyone know the ablities of any player, in game time, through personal scouting, game films and talking to the individual players coaches. All the way back to grade school, in some cases. Pretty much a good old boy's get together at night, after the run time drills are done for the day, at those Combines. Usually a great steak dinner and cigars and Scotch after wards. All paid for by the NFl team owners association. Let's not forget the hookers and the time away from the wife for some of those guy's...Priceless! Good Luck