I wouldnt think it is true that Knotts are waiting for the final OK, After all construction has actually started, but its only been in the form of land clearing, track arriving on site etc. I suspect XCellerator will go vertical Early January, and will still meet its Opening day in Early/Mid May. after all, its not a Big Ride to build, so it shouldnt take Intamin too long to complete the circuit.
Also, I have heard news about this coaster that may disapoint some, I have heard from sources that The final Bunny Hops which WERE planned for the ride's finale have now been abandoned and scrapped, Even though it was strongly rumoured on all coaster forums all around the net. Infact if you look at the artists impression, you may notice there thats they are not there, so basiclly, I just thought I would definatly confirm it to you all right now. In my opinion, although the bunny Hops would have been nice, I will still be happy with the final outcome as the ride still looks awesome enough to me(Cant wait to ride this next year hopefully)