Changing the pin to a grade 5 or 8 bolt is what I suggested to Chris when he called yesterday

In any case it would probably get you going for a while at the very least and if you end up breaking the end of the shaft you still aren't out anything because you've got to replace it anyways at that point. In this case you're pretty much just out the time to try it.
Another suggestion is to see if that guy that did the seal repair has any connections to get the new end cheaper or other repair tips.
Rick