any goal indicators for paid membership sites?

I’m looking for perhaps plugins that allow you to put some kind of a “goal” indicator, like a thermometer or speedometer like indicator, on a paid membership’s home page that can show how close you are to reaching a given income from subscribers based on active accounts and payments.

This may sound weird, but what I’m trying to do is set up a MU site for a kind of “challenge” event. Each participant gets a separate site in the network and needs to get friends and family to support their participation by signing up for one of the monthly contribution levels, say $5 or $10 per month. If their goal is $250 per month, then we’d want something that shows how close the participant is to reaching that goal for the current month.