Tongue-in-cheek jokes aside, the White War Tiger was originally an exclusive bonus for players of RIFT over in Korea. The mount has been ported over to the US version for a limited time so that more players can access it. If you've already got your wallet out, just log into the main site and check in the same spot for the game edition upgrades to get your very own tiger. While it may sparkle, you can take solace in the fact that it does not fly.
[Thanks to soundersfc.tif for the tip!]