I was just talking to one of my buddies about this today:
It would not surprise me in the least if a couple of the big guns we are still after have already verbaled to Urban, but Urban has told him to wait to commit until on of the all-star games they are playing in or National Signing Day. I remember Urban at Florida, he always had huge players committing to Florida on those days. Nothing better than good publicity on national tv.
Also, a while back someone asked Urban about the 2013 class and he basically shook it off as like "yeah, we've already got it locked up".