I would really like to hear progress reports on that one. Does F# Mono now correctly implement tail recursion? The most recent release notes suggest it does.
I've only followed F# Mono from afar as an academic interest, but I've seen comments about tail recursion causing stack overflow, while in .NET I've easily calculated the millionth power of 2 and very large fibonacci numbers with simple recursive algorithms (i.e. it really did recurse a million times).