I dug out this thread while looking to see if anyone else had commented along such lines; I'm really quite interested myself, even if just for the sake of gapless playback (which I'm really missing on the N9). If anyone has made any progress towards Rockbox on the N9 (even if just finding out specific issues standing in the way), please let us know, and I'll follow up here myself when I get the chance to set up a proper build environment and try and at least compile the Maemo/N900 version for a Harmattan target.