I bought an 860 from someone in Taiwan, but it seems to have been a one-off. It seems to me that any Z's sold outside Japan are either through a specialist importer like Trisoft, Dynamism or Figlabs, or are second-hand.
Provided the seller has a good rating, most people who own zauruses tend to look after them very well - either because Z's are not cheap, or because they are not easily repaired, or maybe because the Z draws a particular type of person who treats his/her equipment with respect.
The only risk with a 2nd hand Z is if the flash is worn out, which seems mercifully rare; and at least the microdrive inside the C3x00 is replaceable!