The message that they are no longer available is gone and they ship in 3-5 days. Could this just be that you order one now and they ship you the new one instead when it's released on Tuesday? If that's the case it means they aren't killing the 1Gb model.
what they probably did is upgraded the shuffle and are going to ship that one instead to all the customers who buy it now. Tuesday launches macworld...they did the same thing with the new powerbooks....but, we'll see in a few days.