An open-source design of the N900s stylus for one of the best open-source phones out there ;-)
Compared to the original this model is slightly more e...dgy but this simplifies printing and gives a little more room for creating a nice finish.
I've included the Blender source so you can modify the pen as you like.
Update:
A word of warning: Since i had to take my measurements of a few pictures a friend of mine took of his original (because i lost mine long ago) i cannot guarantee sub-millimeter accuracy. Plastic parts are easy to modify after printing for making them fit but aluminum and alike are not, please keep that in mind.
One more thing... If you take the .stl and it's just about a cm in length and too narrow to print: Simply scale it up 10 times equally in every dimension. The length should be 9.9cm.
3d model print parameters
This particular part was printed on a BFB 3D-Touch at it's best resolution (0.125mm) but i think it should still work out at 0.25mm. The material used... was PLA on a PLA raft (ABS is way too flexible). The small cylinder you can see in the rendering was necessary to slow down printing on the back part, without it the handle just melted while printing.
After printing you should start with removing leftovers from the raft with a file or similar and continue with sandpaper (in my case it was 120 grain) for a nice finish. Be carefull with the back part (the part sticking out of the case) so you don't sand it down too much and also leave the edges at the bottom side in tact. I did both things wrong so you don't have to ;-)