I can certainly tell you, the last bonnet in stock in Australia was sold a few years ago to Rob at the zed factory.Trevor at Brighton Nissan was kind enough to tell me.
Not quite correct - I bought 2 x vented bonnets from Brighton Nissan in April last year when I "Liberacied" the girl who stopped at the green light.
These were remanufactured from Nissan in mid 2009 from the dates on the part number stickers.
If you look hard enough you can find them (ex japan now)
I bought two so I have a spare in case I have another incident at a green light !