What this 'mod' would be, is the ability to rob generic NPC's (Prospectors, Travelling Merchants, NCR troops etc etc). The idea would involve adding dialogue to the NPC along the lines of "I'm robbing you, hand over your stuff". Then hey presto, your the next dike Turpin. Although it would obviously be a lot more complex than that of course. First off, it should factor into account the players skills for intimidation which would be Speech & Barter. The higher these skills, the higher the chance that your victim will comply. Now thats the basics of it. Other things that should be taken into account are the total value of all the NPC's items (higher value, higher chance of resisting) and if any other NPC's are following the victim NPC or vice versa (Since if the NPC is following/being followed there's a high probability that they're in a patrol/caravan). If the NPC has companions, the chances are even greater that your heist will go badly and end up with you being slotted in the face. One last factor to take into account would be the players weapon. If you're equipped with a pool cue, chances are that you'll be told to take a hike. If you're equipped with a shotgun for example, the victim probably knows something bad will happen to one of you and be willing to submit to your demands (even if you have no ammo ) Now this would affect your relations with the associated party obviously, but it would be a good thing for playing specific types of character.
Just getting that idea out there. Hopefully someone who's clued up could do something like this, sadly that's not me as I am bloody hopeless at all things computery.