The Transformer Prime is available for pre-order on CDW, Amazon, and various other retailers in the US and Canada, indicating that a release date could be coming soon. (theverge.com)
Those could be deal breakers for you, but if you're interested in checking out the 6X, it's currently available from Amazon, Newegg, Best Buy, and various other retailers unlocked for $ 249. (9to5google.com)