I am pretty sure that is exactly what RnL does. I was amazed when it sounded like voices were coming from the people in the room's direction.
I suggested an area-of-effect type voice chat before and it got mostly denied but I still think it is a great idea.
Right now, I rarely play on server when there are more than 12 players, a lot of people have mics and people are always speaking over eachother and therefore missing when someone is saying "___ Is the traitor hel-"
I feel this would bring us back to how TTT used to be, you would actually want to try and trust some people (hang out in a group) so you can hear them/they can hear you nearby and so you don't get caught alone by a traitor. Right now people pretty much go off on their own and hope they win as an innocent.