I don't think that MeeGo based on the moblin-maemo hybrid core will be ready for even Q3 or Q4 2011. The integration started in February, and having it finished in less than a year would seem extremely optimistic.

Just like the N900 was slightly delayed and the N8 was also a number of months late, I think that the same kind of problems arose in the N9 development. This is the reason Nokia wants a software guy as CEO. They want to eliminate the product delays because of software problems that Nokia has had in the past.
The fact that the head of MeeGo devices leaves could also be because of the delay.

Currently Nokia really is a manufacturer of relatively under-powered devices (with the exception of the N900, but that was not intended for the mass market, average consumer). Samsung introduced her first device with an ARM Cortex A8 core in february 2009 (i8910), and Nokia won't have a Cortex device, intended for the mass market, for sale before 2011!
That is 2 years late!

I still think that the N9 will be announced at the MeeGo summit, but it will probably ship in Q1 2011.
Nokia needs a good high-end smartphone/mobile computer. The longer it is delayed the bigger this problem will become.
But I must say that the N8 is a good innovation, with wonderful new features, and I'm looking forward to getting my hands on one even if the device doesn't have a Cortex processor.