Nicholas Francisco is one.
When a Family Man Disappears: Tale of a Deadbeat Dad
Left his pregnant wife and 2 children, abandoned his car.
I couldn't find an archived thread, but there was a poll on whether people thought he was alive or dead. At the time, it was about 60% alive 40% dead.
There was another lady who left her daughter duct taped to an ice machine or something very strange like that. She turned up states away, months later, but that was clearly a mental breakdown.
So while there are examples, I do agree that it's very rare but sometimes the improbable does happen. Personally though I'm more in the self harm camp, sadly.