Richard,
I'm not sure if you are still looking for examples, but we have been piloting Moodle badges for a couple of months now (I managed to get a 'working' version backported into 2.3 for a couple of months, but upgraded to 2.5 now).
We have been giving badges for Moodle usage for staff and students, as well as for our last CPD day to all staff who attended training sessions (over 150 staff CPD badges have been awarded already).
We are (hopefully - dependent on discussions from pilot) planning on rolling the Moodle badges out across all of our students next session.
You can view our badge designs and descriptions here.
If you want any more information, please let us know.