MonoDevelop 4? I'm using 3.0.3, which seems to be what their website advertises as the latest version. Maybe I'm missing it. Should I be building from source?
up to you really they released 4.0
http://monodevelop.com/Download
it looks a little prettier, but besides that nothing has really caught my attention. it also seems to throw exceptions more frequently(throwing exceptions, not crashing)
you need a fork of the fsharpbindings project https://github.com/xamarin/fsharpbinding
have you tried using fsharpx from nuget? monodevelop has nuget support as of now. https://github.com/squidge/monodevelop-nuget-addin/tree/xs-n...
I also just built fsharpx.core and fsharpx.http with monodevelop(right now) and it built fine for me.