Status report: I've came a bit further in compiling it for N900, mainly because of kolab.org repository: which has lots of calligra dependencies allready compiled and downloadable for N900 (compiling them by myself was too painful). But I've hit a major roadblock: I was trying to solve these errors: e.g. on my desktop ubuntu 64bit, file "kabc/stdaddressbook.h" is in package kdepimlibs5-dev , but installing this package in maemo sdk didn't help (and dpkg -L doesn't show this file for kdepimlibs5-dev package, so it's not there on kolab.org's version). If anyone's interested, I made these steps in sdk with these results:
1. add kolab.org deb and deb-src repositories to /etc/apt/sources.list as noted above and run "apt-get update"
2. Here are commands that I've run next: commands.txt
3. Here are results of cmake command: cmake.out.txt and cmake.err.txt
4. Here are results of make command: make.out.txt (you may get more text, as I've re-run this command few times, so if you run it for the first time, more logs with information which sources are being built will be printed) and finally make's error: make.err.txt

Does anyone know of different repositories with kde packages for Fremantle? Or how can I tune these packages (change some options after apt-get source SOMEPACKAGE) to be built in a way that generates missing files? When I succeed, I plan to upload all needed sources from kolab.org to extras-devel and then calligra package itself. But I'm blocked atm, I give up for today, will try something more tomorrow in the evening. If you were involved in Freoffice development or know someone who was, you can also give me a tip who to ping (I suspect they might have faced same or similar problems). I'll try to contact kolab.org guys, they might help.

Edit: resources that gave me more or less valuable information:
- calligra-devel mailing list
- building KDE in Madde (I was using these information when I was trying to compile KDE dependencies earlier, in SDK - not MADDE, but instructions were a bit helpful either way)
- Building Calligra on Windows - suprisingly, it describes more cmake command line parameters (like -DBUILD_mobile=on, etc.) than "standard" Building Calligra page and Maemo-specific instructions (which tell something about Freoffice, but are garbage anyway)