I believe that the port on the 30" LED Cinema Display will depend on the ports on the graphics cards on the Gainestown Mac Pro. Since Apple did not update the 30" Cinema Display at MacWorld, I am assuming at this point that it will be a simultaneous release with the new Mac Pro whenever that gets released.
So, if the new Mac Pro has dual Mini DisplayPort out, we'll see the 30" LED Cinema Display with Mini DisplayPort.
If it has regular DisplayPort out, we'll see it with regular DisplayPort.
Personally, I believe that it will be Mini DisplayPort and the Mac Pro have Mini DisplayPort, as Apple will want people with the newest laptops to be able to buy an even larger display without the turn-off of an additional adapter.