You can always try beech. CVA used it in several of their production guns including their Kentucky rifle. Obviously durable; it seems to me to be a little lighter than maple or walnut. In my opinion, maple, cherry, and walnut are about the same when it comes to weight. I've never seen beech figured all that well.
I know once up a time GunstocksPlus had cut some sassafras stocks but I don't think it's one of their normal options. They were selling them on some sort of clearance. Here is their link:
www.gunstocksplus.comI have no knowledge of butternut,
but the point raised about holding fasteners better, etc., is a very good point.I read once where applewood was also used way back when. I don't know anything about the weight, density, figure, etc., compared to the others. Maybe somebody else has some experience with applewood, or other fruitwoods like pear, and others.
If I have a chance one day I might try pecan. I've thought about that for a while.
Anyway ... If I didn't help the answer to your question I hope I gave you some other ideas.