I've been following this very, very, closely. I adore my N900...I just wish it was a little closer to my beloved Debian than it is...not to mention with the closed source UI code replaced with open code. I was tempted to do some of that work myself (and/or join some of the people doing similar things), but it was hard to justify the time cost on what is essentially a dead piece of hardware.
...with the potential for new devices however....things become a lot more interesting.
Personally, I never really bought into the Meego changes...I felt too much of Maemo's "Debian" roots were lost thanks to the merge with the more Redhat-based Moblin, and I'd be much more interested in going back the other way, though the developers working on the continuation of Meego (Nemo et al) have done amazing work, cumulating in Jolla's new phone running Sailfish. I concluded (as, it seems, have many others) the best approach for my aims was to take the working Maemo 5 system and slowly rewrite the closed components one by one whilst simultaneously separately rebuilding the foundations on top of a more standard Debian base, essentially so you can have operational testing of things like communications features much quickly. There's been a lot of good work by the Maemo community to this end.
All in all, very exciting. I'm hoping to order a couple of boards to revitalise a damaged spare N900 I have here, and if it works out well, my main one too