Some people in this country still have a since of honor and pride, which is becoming rare these days. Ethics can be a individual trait, and be seen differently in different people, and on a case by case basis depending on the circumstances.
I can't tell you what is right and wrong here, or try to explain what some just feel in their heart. I would not build this without the permission either, but that is Me. If someone offered Me a MILLION, well that's a lot of money for a cue and plenty to go around, so I would probably contact the gentleman also to even commission the cue through him or ask permission. I'm not a greedy person, and I could be happy with as little as half that money, as to compensate him for My own piece of mind, and I would hope He would give his blessing and possibly even some advice on the build in return. What You feel is right, is up to You, if someone else has to tell you what's in your heart, then possible You will never get It.
You can sit here and try to catch someone up in their own statements, that's easy enough to do to almost anyone, but from what I see at least he gives a #^%*, enough to think about It, and if He could live with himself or not with such a decision. I tend to agree That's It's not completely ethical, but again that's Me, and It's obvious that some would do what It takes to try a justify It. For Me I could not without the man's blessing.
True some things that have become industry standard once came from somewhere originally, but since patents weren't a issue, and they are only one element of a cue, It's not really the same thing. Even artists have used, and copied brush strokes from past masters, or used the same canvas materials, but that's still not the whole painting, only different elements to form their own ideas, and create an original from. Besides that If the guy is still alive, then there is a chance he may still be able to sell his creations. That is if It's not like there is no one alive to still make It. Your talking about straight up copying his design from one You saw, not just using elements in your own design, or building a tribute. While even using some elements could be questionable, there is no question about totally copying someone else. That's just My opinion, and how I feel, nothing more, so If You feel the need to pick My post apart too in order to justify Your ethics then Have at it. Possible we were just raised differently, and see things from a different angle.
Most Cuemakers aren't ruthless business men that are good at justifying decisions like that, there are many more profitable trades that they would be more suited for if so, and could make a much better living doing. They have to make a living, but not dreaming about taking the world By the horns or anything, and looking for ways to copy others. getting ideas to bring out one's own creations is one thing, completely copying is another IMO. Greg