the best way forward for Nokia may be to use the fabled and currently vapourware Meltemi and their hardware expertise to start knocking out phones similar to the ZTE blade /BladeII and others which are mid spec Android devices getting pushed out at £100 or so. Chuck the Swipe interface from the N9 on them to wow and seduce the punters, and allow these devices to be "unlocked" or customised by the community like Android can be (think cyanogenmod), and there may be a real chance for them to be very disruptive in the market.
Why go through all that effort when they can just slap Maemo 5 for the high end phones and tablets and Maemo 6 for mid-end. Job DONE!!!