Some time ago I've sent the patch for the driver with sorting support in queries. Samus answered me how to implement it properly in the context of the design. At that moment I had no time do that and I've been just using my version of the driver until now.
Now it's time for me to use linq with the mongodb and I want to implement sorting functionality for the current version of driver. As I can see there were a lot of changes, so if someone gives me instructions (are you still need in the Query class etc), I will make the contribution