We just released an open source module (GPL V3) for the OXID eShop (<4.0.1.0). This modul enables each user of the eshop to upload a user picture/avatar directly as a file or via Gravatar. This user avatar is then displayed next to all the users comments and recommend lists. More details and downloads hereor at google code.
Enjoy the modul an feel free to give us some feedback.