I live in the UK and had mine ordered by a great seller off ebay who's keeping very good contact with me. He ordered it at roughly 4:15am EST 16gb Black Wifi and Gray Smartcase.
He told me the gray smartcase had shipped, but hasn't contacted me since. He said he would let me know as soon as there were any shipping updates, so i'll assume it's still "not yet shipped".
I would love to know how they are sorting through them at the factory in china. They are clearly not doing it first come, first serve. You might find that they process the payments in order, but some payments might go through fully on apples side before others - and obviously they won't ship the ipad until the payment is 100% complete, so the orders are a bit jumbled up.
Obviously supply limitations of different models is a another factor. You guys must also remember that when it says shipped, it's not immediately put on a van and is out the factory. It will say shipped and then they will all be picked up at the end of the day, or maybe two or three times a day due to the amount of orders. What i am saying is, if one of you had your order shipped 4 hours before the other, they both probably left the factory at the same time. Or maybe 'Prepared for shipping' means it is packaged ready and they are waiting for the truck to turn up to pick all the ready ipads up.
Just some theories
This is an evil game, isn't it ? there is nothing worse than something that you wan't so bad being totally outside of your control.