I am pretty sure that if Quim could answer, he would have answered already.

Perhaps, depending on technical-timing-financial factors, they don't know yet.

There are many possibilities... Maybe they can do it, but they would need to hire 10 more devs and need the approval of a higher up to do it. Maybe they can do it, but in order to do it, Maemo 6 wouldn't release on time and need to work on the re-scheduling. Maybe it can't be done, but they are working on some kind of trade-in which isn't ready yet to be announced.

So many things that can happen! And one thing will happen for sure: people will hold Quim and Nokia accountable for what they say, will expect their word to be fulfilled, and there will be hell if it doesn't (remember the N900 launch delay?).