Quoting the official Palm blog, it sounds like it's not dead, just postponed to a future iteration:

"Jeff Hawkins and I still believe that the market category defined by Foleo has enormous potential. When we do Foleo II it will be based on our new platform, and we think it will deliver on the promise of this new category. We're not going to speculate now on timing for a next Foleo, we just know we need to get our core platform and smartphones done first."