We have:

• a Mappamundo with the 181.57 serial number (on the case-back) offered by qualityvintagetimepieces.com (a dealer in Canada), and marked "On Hold" -- http://www.qualityvintagetimepieces.com/vintagechronographwatches.html. You can see more photos of this Mappamundo HERE.
• eBay listing of this same watch (based on serial number on the case-back), by a seller from Canada --
  http://www.ebay.co.uk/itm/360403389127
• this thread started by Mike, who has a Canadian e-mail address and says that he has recently purchased a Mappamundo.

: one up on Ebay now - for those not convinced by overwhelming
: evidence. this one comes with the benefit of a wholly inaccurate
: desciption of the 'rarest and most sought after' Heuers.

:
: http://www.ebay.co.uk/itm/RAREST-VINTAGE-HEUER-EBAY-1970-MAPPAMONDO-EUROPEAN-MARKET-NOS-NOS-/360403389127?pt=Wristwatches&hash=item53e9b74ac7

: I am in no way related to or associated with the seller. At least I
: hope not.