Yeah i remember, and perhaps the german "dreiradler-forum" may help you, if you didn`t knew aubout them.
Many airheads in there and if you ask, there are often wheels left.
On the other hand, the so called "2-ventiler forum" could be a good source.
The brother off the wife from my wifes sister, works at mobec. It is good old german work, for money, perhaps we can help.