I bet nobody of you read producer's letters. It's stated in the last letter the mount system will come this summer.
http://forum.square-enix.com/ffxiv/t...805-20-2011%29
look at the very end of chart.
(Remember, these are our plans until summer 2011!)
and it's been already clarified "until summer 2011" means from june to august/september (dev post)

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