I did some research on that model a while back. It may not have been very popular at the time for some reason. It had a short life and many were liquidated at great prices. It could also be they were very popular, and they immediatly saw the opportunity to extend the functions in updated models.
As I noted on SAKwiki there appears to be some closely related models, or possibly different names for the same model.
It appears to be not too common in the hands of collectors at this point, but with the evolution of the voyagers and travellers, I suspect it's collectability will rise (shhh don't tell anyone).