In the US there seems to be a number of Ebay listings for Z11 preorders, though you're going to pay a pretty steep premium through those sellers as they jack up their prices due to import fees and PP/Ebay fees. Ebay provides you with very good buyer protection so there shouldn't be issues with buying on there unless you're buying from someone with 0 feedbacks.

You could also make a WTB post for a Z11 in the Computer Hardware section (click for link) on this forum. Always use escrow while buying and selling here if you choose to go this route.