No you would not. The unlimited plans cannot be added to existing lines or new lines of service. They only people that can have them already do. They can choose to keep them or downgrade to the new tiered plans. But once it's downgraded, you can't go back to unlimited.
The only unlimited plan that can be added, and correct me if I'm wrong, is if you pick up the old first generation iPhone. It is 20 for unlimited Edge data since it wasn't a 3G phone. From there you might be able to swing unlimited data.
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