You mentioned warbirds, so I'll toss this one out as a possibility since a stroke is recommended:
http://www.airborne-models.com/html/...sp?ProductID=4
I do not have personal experience with this plane. A LHS owner has the plane and he says it is one of the best flying warbirds he has ever flown. He says it does not have bad stall charsacteristics.
I do have a kit built Great Planes Corsair 40 with an OS 70 four stroke. My plane does not pretend to be "scale." GP specifically says it is a sport plane that resembles a Corsair. This plane stalls like a trainer; it just drops the nose until it picks up enough speed to fly. Thelanding gear wires are a bit soft though and they bend easily when landing on grass.
The primary negative to this plane, and almost any warbird, is the fact that it has retracts. You mentioned a rough field, which means the gear will take a beating.