A very interesting thread, speaking from personal experience only. I have found the make of nib has been unnoticed by my customers.
They have however looked at the pretty patterns to decide whether it is any good before trying it.
None of them have been unhappy with the Chinese nib they have had (most if not all have said Germany on them in one shape or form).
I have only ever once been asked to supply with a spare nib and he wasn't worried which one as long as he had a spare.
I think a ready reliable source of nibs would be good for some members but how many and how often I suppose is what you're trying to discover.
I have never had to swap change or shop for a nib alone so I wouldn't rely on me as a potential customer.
