Ah yes, the 40 meter height limit. Could Merlin change their plan and resubmit designs to the council for a larger coaster that's a little closer to Stealth's height? A hyper coaster would be ideal as there isn't a coaster at Thorpe (or anywhere in the UK) that offers a fast and floaty experience that a B&M hyper offers.
The only other sorts of coasters that could offer a new experience at Thorpe would be a woodie (which is highly unlikely), a flying coaster (unless it was something similar to Tatsu, it wouldn't really fit in with Thorpe), a Mack mega coaster (high speed lift and low, quick, intense turns and hills?) or maybe an Intamin coaster like Fahrenheit.
(this sort of coaster would fit within the 40m height allowance; Fahrenheit being 121ft tall)
That is unless they have a world first concept in mind?