Sounds like we're mostly on the same page. The tree being described sounds like what I've known as "bodark," as Dave said. Osage orange, burdock, or hedgeapple, I'll bet it's the same tree. Bodarks also produce a large green fruit that we called 'horse apples' because horses liked to munch on them. They have a milky fluid in them. The wood is very hard and strong, but most of the ones I've seen have a tendency to be rather crooked and knotty.
I have a cousin who tools pens out of bodark wood from the farm north of Dallas. I just snapped this - sorry it's a little blurry:
