Seems like it's already packaged for Mer... So... ¿?
http://www.maemonokian900.com/maemo-...-calligra-2-4/
It also seems like "Usability Enhancement of Calligra Mobile for N900" is being done by some "SJCE Students" (¿?)
http://community.kde.org/Calligra/Calligra_Mobile
I think it would be really nice that it could be "backported" to N900... Or maybe will be some time we all "move on" Mer+Nemo...