I think there are a couple of pieces of evidence that strongly point toward Trayvon approaching Zimmerman for a pre-planned attack, as opposed to defending himself because Zimmerman reached in his pocket.
To me, Rachel Jeantel not contacting anyone, as in neither police nor even friends/family of Trayvon after supposedly thinking she'd just heard him get tackled by a stalker he was afraid of, and not doing so for a full month... and then actually NEVER voluntarily contacting anyone but instead having to be tracked down via phone records and then having to be pressured into talking even to the Martin family attorney... is simply not consistent with the idea of Trayvon rigorously defending himself after an unexpected and unwanted encounter.
What it IS consistent with is her knowing full well that Trayvon intended to whoop Zimmerman's behind as she put it, and possibly even encouraging him to do so. When the phone went dead as she supposedly heard someone in distress saying "get off me" and the sounds of a tussle, this would not have concerned her at all if she understood it to be the sound of an expected, planned, and relished assault by Trayvon on the snitch cracker who'd been disrespecting him by monitoring his movements.
In an interview with Piers Morgan, she tried to claim "creepy butt cracker" wasn't about perceived race (despite admitting it was at trial) and said instead that it meant "someone actin' like they a security or police." In other words, she seems to be implying that Trayvon understood that Zimmerman's interest in him was out of suspicion and concern and that this was a nosy snitch, not a threatening rapist, abductor, or attacker. You don't attack a nosy snitch out of fear, you attack them out of irritation.
She also said Trayvon said he wasn't going to run. That's consistent with him being free of any real concern that Zimmerman posed any threat to him. It's consistent with Trayvon feeling bold and ready to confront.
Now, if it were true, as some here are suggesting, that Trayvon merely meant to confront the man and demand some answers, but then ended up throwing a punch in reaction to the pocket grab by Zimmerman, then we are confronted with some other problems.
If Trayvon was merely seeking to neutralize a threat and not acting out of anger and exultant violence, he would have called out to Witness 6 (John Good) and said something to that effect and asked for assistance in subduing the threat. His silence and ongoing, single-minded violence, as attested to by that witness, is far more consistent with a violent young criminal lost in his own rage and heedless of consequence or surrounding. Taking out all his built up frustrations.
If you're merely trying to stop a threat, why keep beating them as they put up no fight and scream in terror? If Trayvon suspected the presence of a weapon then why was GZ, who by all evidence was being dominated, ever able to draw and fire the weapon, especially such a direct shot? Why weren't Trayvon's prints on the gun if he knew about it?
As for the old claims about Zimmerman ignoring the dispatcher, the evidence remains consistent with him following the suggestion not to follow further. He said "okay" and then a long span goes by where he doesn't know Trayvon's location and sounds calm and matter of fact, and stationary or slow moving. I note that the person who quoted that exchange left out the part where he said "okay."
Who can offer a reasonable explanation for Jeantel not contacting anyone? The only good explanation for her behavior, hiding, lying, and loathe to testify or even speak with friendly people, is that she knew Trayvon's intent was an attack. That also fits her comments about Zimmerman not having his gun out, him getting whoop butt, him acting like security, and her believing that Trayvon swung first.
The trail of physical evidence and the sounds of the assault were shown by witness testimony and scene examination to have placed the initial point of attack at the T junction, then rapidly moving south.
Also, the implication that being white is an impediment to reaching good conclusions on this case is exactly backward. The African-American community has shown from the outset that it had major problems viewing this case objectively and unemotionally. Those who "sided" with Zimmerman's self defense claim have been vindicated by every evidence or law-based development as this has all unfolded.