I wrote a simple plugin for Gravatar. I am planning to put files on Extend, but I am still waiting. You can download it from Google Code for now, please visit this plugin's homepage. You can find a download link and know how to modify your theme in the page.
It is relatively simple:
- Gravatar Email field - This plugin doesn't use user's registered email.
- Email Verification - Users need to own the Gravatar Emails which they input.
- Support Default Image
- Size customized (1..80px)
I hope I can hear your thoughts about this plugin.