i don't think there will be a single 120 version that's thicker than the h80i
280mm, possibly
Well I'm guessing it has to do with the spec, The H100i is the best 240mm cooler they make where as the other 2 might get big brothers i.e thicker rads etc... so the "X" will be reserved for them, Would make sense, If not then the I aint got a scooby.
What if you consider that the H100i GTX is the flagship of the 'small' blocks and there is still a flagship of the big blocks to come.
Small block - H80i GT
Small block - H100i GTX
Big block - H110i GT
Big Block - HXXXi GTX
JR