all of the above could be correct but honestly - if you want a special one of from a manufacturer and he decides there is a market for it of course he will then produce and sell - for a bit less is a bit rude though
No sorry you are wrong. When someone says verbally and in writing 'I will only make them for you and no one else' (call me old fashioned) but where I am from that means they wont sell them to anyone else.
If they had said, 'you pay for all the dev work, we'll charge you top dollar then knock them out on ebay for less then you have paid for yours' that would be a different conversation.
They didn't say that.....
Holtworks do beautiful work. You may also consider Joe Maxwell who I think will make you a tank. Terry Weedy also makes and supplies them ~ I am pretty sure he does a B50 tank anyway. Top bloke, you wont go wrong with Terry! (plus LOADS of other alloy tanks for side cars WASP etc, trials AJS. Matchless, BSA, Aerial, scramblers Metisse, BSA, CZ, Pursang etc etc etc