Allow members to choose amount of rep given

[McCarroll21]

This isn't insanely important, but I have thought this would be a good mod for a while now. If I have just missed it, I apologize and a link to such a mod that exists would be helpful.

Here's what I would like to see:
When giving reputation to a user, the reputation giver has the ability to determine how much of his rep power he would like to give for that post.

I have found that sometimes on my site, people with higher rep power don't give out rep as often as they would like because their rep power carries so much weight.

Example:
A user likes a post, and wants to give rep, but has a rep power of 42 and doesn't feel like the post is worth that much. He should be able to give a certain amount up to the 42 maximum points.

Maybe an option to give 25%, 50%, 75% or 100% of your rep power?