This is not a question, just information hoping it will help someone.
Host: Fedora 15.
VBox: 4.1.0
Target: Slitaz 3.0
I can confirm that I have managed to install Guest Additions on Slitaz 3.0. Now I am in full screen mode and can share folders.
There are a few key steps to follow:
(1) Install packages slitaz-toolchain, linux-headers, linux-source, linux-drm, bzip2
(2) Mount the VBoxAdditions iso, cd into the directory, and run as root ./VBoxLinuxAdditions.run
The modules should get built. It will give some messages about adding stuff to /etc/init.d. It can be safely ignored at the moment.
(3) Open /etc/X11/xorg.conf. Uncomment the keyboard and mouse sections (only). Somehow the script comments these out. Leave the ServerLayout section commented.
(4) Add the modules vboxguest, vboxsf, vboxvideo to the load modules text box in the initialization tab of the control box.
(5) reboot
And voila! It should work. Hope this helps.
CC