This was inspired by Other language localization (and I'm sure others)
I only speak one natural language, but can understand the frustration as-well-as appreciate the value of multiple languages.
However, a cloned SO at http://stackoverflow.fr is a the wrong approach.
Something more akin to the Wikipedia model, http://fr.stackoverflow.com where all questions are reproduced and users can translate them.
Questions (and answers) move to a new language will become
community wiki and offer no reputation (however badges would be a fitting reward).
The benefits would run both ways, I'm sure there are many talented programmers in India and China who could add to and expand SO.