depends on what new cpu features they're using. already know n900 support armel and armhf, the later used for meego ce. building for one (n9/n900) will help the other.

it was the whole idea behind hardware adaptation team in meego. sailfish will have a set of features that are harware specific, thats what needs targetting. don't forget cpu is only one device. cellular modem, gps, bluetooth all need drivers which may be different. we already know we can use dsp codecs from n9 on n900, so thats one question answered.