I've had it happen to me many times with Amazon.
Some frustrating ones at that. Ordered a tent after our old one tore, planned on setting it up in back yard over the weekend to introduce my daughter to "camping". Well, it finally shipped on Saturday, two days after it was supposed to be delivered. Not fun having your 5 year old all pumped about "camping" and then having to tell her it's going to have to wait till next weekend.
One "in stock" item I ordered from Amazon took over a year to get delivered! haha
In the end, it was worth the wait:
http://i1303.photobucket.com/albums/...psbrvd2k2s.jpg