Well I guess this one has everyone stumped?
Not much I can give in terms of clues...its a Fokker project and has a project number P-XXX. It was a development from the S-11 and S-12 trainers. There is mention of it on the internet including the 3-view.
I'll leave it a little longer but I have to go out later, so if no one comes up with it by then I'll identify it.