The best I can think of fora CHA LSC 3.0 would be some sort of haggle system. Where you go up to a shopkeeper, and you "haggle shopkeeper". From there, the you try to convince the shopkeeper to give you via commands like Chakramold or Shadowbox. Intimidate, Flirt, Polite, Rude, Aggressive, etc..
Actual success would depend on your CHA if you're told to do specific commands, otherwise it would depend on how well you could judge which way to act. Discount as a temporary, say, 10% off -- maybe last a few in game hours, or good for one item. CHA would go up slowly as you continued to try, even through failure, and you could only do it once in a great while per shopkeeper. Failure/Severe Failure results in raised prices for an extended time.