If it were mine, I would try to fix it myself. This video shows how to disassemble the N900.

http://www.youtube.com/watch?v=aVEHm325-z8

It looks easy - just remove the screws and disconnect the cables. The actual LCD display is covered by a piece of glass so the repair should be relatively inexpensive if the display still works.

I haven't ordered repair parts, but I have seen threads on the forum that mention sources that are known to be reliable.

Good luck!