I highly doubt the Slate is dead.....just what they originally showed is dead.
HP is probably going to produce the Slate. However they just announced they are acquiring Palm, so they are most likely going to redesign the Slate to run Web OS instead of Windows 7.
For a web enabled touch device, Windows 7 is bloated, has high hardware requirements (and therefore isn't really power efficient...see the Archos and its battery life) and isn't really designed around a "touch" interface. I'm not saying it's a bad OS, I think HP didn't see it meeting what they envisioned the Slate to be, an instant-on web device that could go a day without a recharge.
In fact, the purchase of Palm was most likely because of the Slate and their wanting Palm's Web OS. It's quick, power efficient, it muti-tasks, and HP gets to design the device around what they want rather than what Microsoft lets them with some version of Windows 7. It will be a viable competitor to the iPad and competition in the marketplace is good.
Not to mention in the near future there is going to be a slew of Google Android based tablets in the pipeline.
[This message has been edited by kslish (edited 05-10-2010).]