It's not a T Rex. RMC will be producing at least one Raptor before they begin working on a T Rex and since there are no new RMC coasters on the slate until 2018, the first T Rex won't appear until at least 2019. Although RMC has yet to announce who will get the first, I also doubt it's a Raptor.
A B&M Dive Coaster would seem out of place, but could take advantage of the terrain.
I'm hoping that it's the new Mack Rides launched Spinner that they showed at IAAPA. Would be great to have one Stateside and not have to travel to Europe or elsewhere to ride the first one. Wishful thinking on my end, as most here would probably like to have it closer to the UK.