Thanks Stretch, me too.
It makes me think of that kid in highschool who could "throw" his voice and make it sound both different and seeming to originate from across the room. This exhaust leak was just passing itself off as something else and it definitely had me fooled. My friend (who gave me the idea) had a Pontiac Bonneville with an exhaust leak at one of the headers, and he was sure it was rod knock. It sounded exactly like a rod bearing, and they didn't realize it was an exhaust leak until the exhaust needed work.
Truth is stranger than fiction.