Thanks for the links. Unfortunately, the shipping costs on every website I've found are outrageous. NTX tools want $9.59 for UPS ground, making the total price $19.48 for a single tiny 6mm wrench! Every tool site I've found is the same, with $10 shipping costs.
There's a dealer on eBay with a few, but they're advertised as having surface wear:
http://www.ebay.com/itm/250832748483
The picture shows the finish quite corroded. I wrote asking for more details on the condition, but never received a response.
Advance Auto shows one on their website but the local store checked and said they're actually out of stock.
I'm hoping someone here has one from a set or garage sale or something that they can throw in a padded envelope for a reasonable price.