OK guys, here it is - UI for full language/layout support for external keyboard attached to N900. Tested to work with both USB and Bluetooth keyboards.

INSTALLATION - enable Extras Development repository and install External Keyboard Support. This should install xkb-data-extkbd package too.


CONFIGURATION - new applet should appear in settings->personalisation . Click it while external keyboard is attached - you should be given an UI to play with.

There is no need to run extkbd UI every time you connect keyboard, only for initial setup and if you need to change layout or setup new keyboard.

"Cannot open /usr/share/hal/fdi/policy/20thirdparty/99-x11-external-keyboard.fdi - no such file or directory" message appears first time you start control panel applet. Just ignore it

WARNING: Usual warnings for using software from extras-devel apply. You've been warned.

UNINSTALLING:
In usual way using Application Manager


UPDATE: Seems that there is a conflict with bt-hid-scripts package, will try to resolve it and will upload fixed version. For now you should deinstall bt-hid-scripts before installing extkbd.

UPDATE2: For some reason me and qole did not agree on how to cleanup conflict between bt-hid-scripts and extkbd, so you have to make choice which one to use. Good news is that if you choose extkbd there is also mouse support available without using bt-hid-scripts, look here
http://talk.maemo.org/showthread.php?p=882380

UPDATE3: 29-11-2010 There should be no conflict between extkbd and latest version of bt-hid-scripts according to qole, not tested though.

UPDATE4: 13.02.2011 Input BT plugin is auto-enabled, no more need to edit /etc/bluetooth/main.conf. Stock Bluetooth UI now has an option to connect BT HID devices. And there is portrait mode support