At the risk of confusing the already muddy waters, I was told (by my department rep, who went to a briefing about the system) that there will be three (or maybe it was codeplugs...) - north, central, and southern. The northern area will be FDMA, and the others, as I recall, will be TDMA.
Remember that this is coming third hand, but the person who told me this is highly reliable, and I trust him to know what he's talking about. I was told this about 2 months ago.
This is not to say that things haven't changed, though!