It's doubtful that the iPad is going to refresh that dramatically by September. It's even more doubtful that Thunderbolt would be in such a refresh – they would have to add PCIe support to their ARM SOC and that doesn't seem trivial.
(Though it's entirely possible it's in the new A5 and they said nothing about it)
(Though it's entirely possible it's in the new A5 and they said nothing about it)