Fish n chips, if locust wasn't available, what about osage orange?
Yes, that would be a very good choice too. Didn't even occur to me because around here it is unlikely to get of any size, but that's not to say it can't somewhere else.
Another one that is good for outdoor use and grows large is Catalpa. However, it is not as strong as osage. We have a lot of that around here compared to the other two. You would want to go heavier in thickness with it. I would go with any of these 3 types before oak.
I asked my buddy about all these, and he said he can't recommend them because they are not commercially available choices. And like I eluded to, there are a lot of variables that can change quality. No real "building standards/codes" for these, just opinions of the quality from one mill to the next of what you might get (there are grade rules, but these types are so uncommon it rarely would be sorted to grade). Just like fish, one person will see it as a trophy, and the next will say it's a forage fish.