Quite frankly, I am a bit surprised c-rpg doesn't have it. For those that don't know what imma talking about: local chat would be like any other chat, just that only people around you could hear it. It can also have a "yell" mod where the area is enlarged.
It could be useful for organizing with people around you while not spamming chat, general joking around with friends (without spamming general chat) etc. Also useful for tossing warnings like "BEHIND YOU! CAV!" Come on, who hasn't wished he could do that?
It isn't hard to implement either. PW mod has it, just copy-paste the relevant files.