Yes, the media's focus on Trayvon Martin has quietly been an effort to maximize his murder's similarity to the assault upon Rodney King, because the media wanted to help Obama advance an agenda. That agenda is that white people (Zimmerman identifies as Hispanic), just attack black people for no reason when they are not causing any harm.
In the Rodney King case, a bunch of white cops decided to beat up a black man. In the Trayvon Martin case, a hispanic man decided for whatever reason to shoot a black teenage kid, who may or may not have been misbehaving but did not deserve to be shot and killed. It all comes down to race in both cases and for whatever reason the media constantly pushes stories that divide the nation such as these.
I think that the media's focus on the Trayvon Martin case was an effort by the media to make the case as big of a deal as the assault on Rodney King. I think that the media wanted the nation to be interested in the case in terms of ratings as well as create a political agenda in the public.
It is possible that there could be similarities between the Rodney King story and the Trayvon Martin story. However, I would not suspect that there was some kind of media agenda to subliminally tie the two stories together. The Trayvon Martin story was a true tragedy and worthy of receiving national coverage and a strong spotlight given that it raises questions to the effectiveness of the laws we pass and how we enforce them.
I don't think that was the intention, the backlash alone could have been awful. People need an excuse to attack one another right now. If we give them a reason for ratings, it would be a mistake. The biggest thing they meant to push for was to bring it to the masses.