If Nokia release Maemo 6 version for N900 I am willing to get it, even it is payed.
As Apple and Google are software copanies and Nokia is at this days hardware company for me it make sense nokia to start upgrading OS of his last devices. Because the market demands it. If not - Nokia will lost his market share very quick.

So I think that we will receive Maemo 6 when it is done.

Regards.