Unfortunately it is impractical. It may happen SOMETIME, but I think we're looking at something like at least 10 years. The cost is prohibitive and the lack of tactile feedback is unfriendly. I think we're more likely to see a touch-screen display become standard before we'll see the keyboard go virtual.
Now what we need is a virtual screen that CAN provide dynamic tactile feedback somehow. That would be amazing and would swing the virtual input device market wide open.
Apple no longer needs to release things on the MacWorld/WWDC schedule. When Apple announces, people listen. Steve knew that the iPhone would make a big enough splash for MacWorld; Apple will wait for that to settle, and make the next big announcement with perhaps some new Macs, then wait, then another announcement, and so on. They are an announcement frenzy machine. :-)
I too recall the Apple card. My parents had one, and saved up the maximum amount to help in the purchase of a beautiful Power Mac 8100. There is no way we could have bought the 8100 if it weren't for the money we saved up on the Apple card. Trust me, if that card were still available, I would have one, and I really wish I could. But not for dumb iTunes songs.. I would save up money for my big computer purchases, just like my parents did when they had the card.
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Zune Update!
I Want An Apple Credit Card