Your best bet is to look on eBay.
For the record (others reading this thread), JIS refers to the most common standard of square-taper bottom bracket interface, used by Shimano and most others. Campagnolo used the ISO interface for their square-taper bottom brackets, as a very small number of others.
So just look for nearly any square-taper 180mm crank. Look in the "road bike parts" category since you're looking for a double crank.
Here's the eBay link for Road Bike Parts --> Cranksets and Bottom Brackets
You can search within this category.
Wow, it's very hard to find anything here.
You have options for new stuff, but it'll cost you.
I have a Shimano XTR with square-taper interface, 180mm crankarms (from 1994, the last year before they switched away from square-taper on the XTR line). But it's not for sale. At least not for the price you'd want to pay
Last edited by TallRider; 11-18-09 at 01:44 PM.
Reason: added eBay link