I think the last thing Nokia wants for their Maemo 6 device is for it to be perceived as weird and that keyboard would definitely be weird. It would be of no benefit for someone who was used to QWERTY or T9 and unlike Dvorak keyboards which claimed to be faster to use than QWERTY, there would be no speed advantage.

I would not rule out a T9 slider (although I wouldn't want one) or a QWERTY portrait slider a la the Palm Pre but I think your idea is a non-starter.