Unclutter in .xinitrc does not seem to run.
 

I put this command at the bottom of my /home/dsl/.xinitrc file:
/usr/bin/unclutter -idle 2 -keystroke -root &

It's running when I do ps -e, but the cursor never disappears.

Does it work when you run it from a console?

I start unclutter with a link in my kde autostart folder and it works perfectly. Perhaps you can try something similar with your desktop environment, whatever it is*. Also, unclutter has a large number of options, some of which are workarounds for when something keeps it from functioning. Read the man page and try some of them out.

*(You really should mention things like what distro and DE you're using when you post things like this. Try adding them to your permanent profile.)