[QUOTE=JG54;9804942]I'd agree that, at the 'lo' end of the spectrum, a modernised OV - 10 seems a pretty good choice. Indeed, I seem to recall that a couple have recently been flying operationally to prove the validity & concept.
I don't know much about proof off concept. There are however at least two in very active daily use with the Philippine Air Force. They are often seen on TV earning their keep attacking the nutters in Marawi.