Giant UK have confirmed that the 2011 Anthem X frameset isn't available in XL. They've said that the 2012 one will be and I should contact them again in September to find out when it'll be available and how much it'll cost.
What other 100mm travel XC full sus frames (that are available in XL) are out there in the Anthem X's price range (the Anthem X frame costs £1190)? Many other manufacturers' only XC full sus frames are hassively expensive carbon things so I can't think of many cheaper ones. The Santa Cruz Superlight is the only one that comes to mind. I know that CRC and Merlin have some cheap Turner Fluxes but none in XL.