I think you misunderstand me... I'm saying what could possibly re-habilitate a self-defense claim, given that Zimmerman already pretty much gutted his own defense by following Martin around when the 911 operator said not to. It would take just such a ridiculous situation that spartanracist proposed: Zimmerman got out of his truck - merely to find an address - when Martin came out of nowhere and started violently beating him. Because that sort of thing happens.
My 0.02 on what happened:
I recall there was a witness Martin was on the phone with, and he described some creepy guy following him (Zimmerman). Now, there were questions about her credibility, especially after the lawyers here & cops got to her (though they seem circumstantial, e.g. she said she was underage, but she was actually 18, said she went to the hospital to see Martin, but did not, and do not actually refute her testimony of the phone conversation), but essentially, Martin knew someone was after him, that person was following him on foot, and the altercation started while he was on the phone. She testified hearing Zimmerman address Martin.
Zimmerman tried to stop Martin physically, grabbed his jacket or something like that. at the very least cornered him in an aggressive manner, got more than he bargained for, and pulled out his piece & shot Martin.
that's manslaughter at the very least. reckless homicide. you could make a case for murder 2 as well.
EDIT: her name was Rachel Jeantel, and
the CSMonitor has more on her.