little of what I've written could be considered "Orphan Works" since I am fairly easy to track down

Yep. The question of its orphaned-ness wouldn't even come up until someone wanted to reproduce it or create a derivative work from it, and at that point, under a hypothetical orphaned-works law, the wannabe user would need to search for the original author (i.e., you) before doing anything with it.

(Ironically, we writers have it easier thanks to Google -- it's dead easy to find the correct attribution for anything I've had published in a non-work-for-hire situation, because that's all collected at my website. The work-for-hire stuff doesn't matter anyway, because I sold full rights to it.)

How does "Dumped Works" i.e. if someone writes something, then feels ashamed of it and disclaims that s/he ever created it, work under copyright law?

I've actually never heard of anything like this; you'd be better off asking a copyright lawyer. I'm really just an interested amateur, and that one's out of my depth -- sorry about that. :(