It's happened on a few SS and monster tanks right at the hinge. Depending on the type of leak that you have, you may want to consider sealing the tank with the motorcycle kit offered by por15 http://www.por15.com.

It comes with a tank cleaner, etcher, and most importantly sealer that essentially creates an inner shell to prevent leakage. Or, try to find Norm on this list who can do this for you.