As of the time of writing all the black versions of the iPadmini Wi-Fi (16GB, 32GB, 64GB) are available for pre-order with delivery slated for November 2, while the white versions are set to ship in two weeks.
But the follow on orders have been experiencing longer delays, and the more advanced models of the iPadMini with mobile data support joining Wi-Fi, have had their release dates pushed back.
In my harsh battery test, where I play videos back to back with the screen set at 75% and the Wi-Fi on to collect email, the iPadmini exceeded Apple's battery life claim of 10 hours and lasted 10 hours and 27 minutes.