I'd like to start a completely locked down private community where members cannot apply - they can only be invited by existing members.  Put another way, new members are "vouched" into the community.  An nice addition to the functionality would be a way to see who vouched for who in the member's profile.

I know there are invite plugins but last I checked, they were buggy based on comments.  Also these plugins don't track who invited who.

Anything that does this?