Rules Integration?

Are there plans for Rules integration? specifically, we're looking for an event based on a user accepting an invite.

The use case is that we'd like to allow people to invite friends to the site, then using rules automatically flag those two users as friends. We're using Flag_friend for the friending side of things, so we can use rules to handle that side. It seems that the two things we would need via rules are:

1) an event based on one user accepting another user's invite
2) some way of accessing the uid of the person who issued the invite

That said, we can envision other scenarios where it might be useful to trigger off rules actions based on invites (like when invites expire, or when the invite limit for a user has been reached).

If this isn't planned, we can use some eval'd php code in rules to test whether a new user was invited. Is there something we can look for in the $user object at the point a new user is created that will indicate that he was invited to the site?