We're interesting in having a plugin developed. We used to use a custom-built facebook application for students, but that was an absolute nightmare. We switched to moodle and LOVE IT!
The only thing we miss is the convenience and ease of the Facebook wall for each class page, so students could quickly, easily, and anonymously post their questions.
We're interested in having something similar developed through moodle...either through something added into a label or as a topic in a course.
If you have any suggestions or knowledge...let me know!