(Replying to myself, since I can't edit the post now...)
More info on F# 3.0 + Mono 3.0 + FreeBSD can be found here:
https://groups.google.com/forum/?fromgroups=#!topic/fsharp-o...
Arch Linux users: the thread I linked also has instructions on how to build/install F# 3.0 and Mono 3.0, if you're interested.