I found a good one at passwordmeter.com I found it on lifehacker It's downloadable from the same site.
All you would need to do is skin it to fit a themed install of vanilla (icons, colors, etc.), and get it onto the member application form. (maybe with a "why?" link that goes to the page w/ the details)
It uses a point system, but doesn't consider the username. It should lose like 10 points for the password being the same as the username (but it doesn't).