I finally found my annoying oil leak and it's coming from the sender. It appears that it's leaking around the swaged body. Anyone seen that happen?

I've got a new one coming from Rock Auto, but I've never seen one leak like that before.

Yeah, sometimes the crimp itself isn't fluid-tight, and then if the sender's diaphragm ruptures, you can get oil leaking past the crimp.

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Too many people who were born on third base actually believe they've hit a triple.

Actually, it is a pretty common failure and one that is hard to find, especially with the "oil pump mounted" sending unit.
The position of that sender allows the drops to fall to the ground, with-out hitting anything. It only leaks when it's running so unless you let the car sit in one place while running, it is likely you would never see any drops on the ground.

Was your sender the "short & flat" type? I find that those have a higher failure rate then the "tall - black body" ones.
DD

You nailed it exactly. It was dripping only while running and it's the short one.