I bought two of these coolers and unbuckled the short handle on each. I attached each end of the buckle to it's mate on the other cooler so that they are back to back.
This makes a great saddle bag. I tried it today on my KTM, and it seemed to work fine. The only thing I did was pull the plastic push buttons on the buckles out so that they locked together better.
It's high quality, water proof, insulated, has a rubber bottom, and comes with a lifetime warranty. Available in three colors, the website includes places where they are sold.
The model number on mine looks like S12KDH if that helps. Mine is grey (matches the bike).
http://www.glaciergear.com/cgi-bin/catalog.cgi?template=product_temp.html&product_id=s12pkdh