if you ever wanted to reboot your device only and not shutdown
and restart again and missed the a reboot button on your N900?
well, here is the solution for you.

what do you need for it:
 1. xterm
 2. PyGTEditor, vi or mc

your steps:

//1. login as root

sudo gainroot

//2. go to systemui folder
cd /etc/systemui

//3.  you need a backup for turning back
cp systemui.xml systemui.xml.bak

//3.1  if  you prefer to use the PyGTEditor, you should copy it into Temp folder
cp systemui.xml /home/user/MyDocs/tmp/systemui.xml

// 4 open PyGTEditor and open the systemui.xml file in your Temp folder

// 4.1 OR user vi:

vi systemui.xml

// 5. go to line where you see <menuitem priority="20" name="Reboot">

// 6.  delete <!-- before it and insert <!-- after </menuitem>

your code should be looking like that:

...
<menuitem priority="20" name="Reboot">
<return>6</return>
<po>osso-powerup-shutdown</po>
</menuitem>
<!--
<menuitem priority="10" name="Soft poweroff">
...

// 8  in PyGTEditor save the file

// 8.1 OR if you use vi:

// 8.1.2 press ESC and :wg to save the file

if you use the PyGTEditor you have to copy back the systemui.xml file

cp /home/user/MyDocs/tmp/systemui.xml systemui.xml

Restart your phone and from now you can see the reboot button,
when you press the powerbutton once :-)