In real life Roddick's 2H BH take-back is rather stiffly produced...so if you copied his it might be different enough to warrant putting it in the game, as well as to compliment his forehand and serve...
Also, as far as different 1 H BHs, two of your compatriots have rather distinct mannerisms...none other than Gasquet and Pioline!!
As far as Pioline's backhand...he didn't use so much of a "loop" backswing...more of a "pendulum" (more or less straight back and then forward into contact...)
Sampras' "ugly" too-open 1H topspin backhand might prove interesting, as well as his signature "flat" forehand...
(to compliment his serve)