Have you ever thought about entering SFML into Google Summer of Code. A mentor is needed and Laurent is probably the only one who qualifies at the moment, so only one project could be done per year. I think it would really help SFML be known and also get new features implemented.
I am personnaly looking for a project to work on in next years summer of code, and if SFML is in I would love to work on it.
You have lots of time to think about this as it's a year away.