How to implement a zero point reputation system
 

I need some advice for implementing a zero point reputation system.

What I want is for users to:

1. Click the scales to give reputation
2. Enter a message that the poster can seen in their control panel
3. Not have any point accumulate for the reputation given

In essense, to just use the reputation system as a means to send a quick message telling the poster what you thought of their post, but without increasing reputation, showing reputation totals in the User CP or showing/increasing bars in the postbit.