Look for an engineering services firm and work as a subcontractor. We're currently employing several guys who are 60 (+/-5). Also... sorry... but try the defense industry. They have insanely low standards.
Can you be more specific about what you mean by "engineering services firm"?
"We won't hire you because you're old, but don't you dare go to those guys who will, because we hate them." lol
http://www.serranosystems.com/