I outlined a three tier system some time ago.
Level 1 is a slight flop, but a flop nonetheless. Contact is initiated by the offensive player. Say you run into Eric Dampier who is out of position. He flops, but he really was hit. A flop nonetheless.
Level 2 is GNob. He gets great position, really does get offensively fouled, but flops as if an earthquake hit him to sell the call. You know who else is "good" at this? Fabs. Very sneaky in real time. Not so much on replay. 10 point penalty, 2 in 1 game is auto ejection.
Level 3 is Derek Swisher. He initiates contact, flops like a chick at a West Hollywood swing dance and then does his PMS pouty face if he does not get the call. 20 points and automatic ejection from the dance, er game. See how often he would keep that up.