A chip analyst for Collins Stewart, John Vinh, believes that RIM "has stopped production of its PlayBook and is actively considering exiting the tablet market." Why? According to his research, the PlayBook's manufacturer, Quanta, has "essentially halted production of the tablet".
Update: RIM's official statement on the matter:
RIM doesn't typically comment on rumors, but any suggestion that the BlackBerry PlayBook is being discontinued is pure fiction. RIM remains highly committed to the tablet market.
It seems kind of crazy that RIM would kill the PlayBook, since the QNX software is essentially the future of the company, and just the other day, RIM was telling us how "the upcoming software upgrade, BlackBerry PlayBook OS 2.0, will help to generate an increase in demand and sell through of the BlackBerry PlayBook over the upcoming months."