Here two scripts to automate the daily 'emerge rsync' with unmasked 
packages.

To use them gust have your unmasked packages in 
/usr/portage/profiles/package.mask by double commenting them out, i.e., 
inserting '##' before them, e.g., changing

   # spider@gentoo.org ; 21 May 2002;   # =x11-libs/gtk+-1.2* doesn't work
   # this is now the gnome2 big bloated mask!
   # (gnome-2 that is ;)
   >=x11-libs/gtk-engines-1.9.0
   >=gnome-base/libglade-1.99.10-r1
   >=app-text/scrollkeeper-0.3.0

   ...

into

   # spider@gentoo.org ; 21 May 2002;   # =x11-libs/gtk+-1.2* doesn't work
   # this is now the gnome2 big bloated mask!
   # (gnome-2 that is ;)
   ##>=x11-libs/gtk-engines-1.9.0
   ##>=gnome-base/libglade-1.99.10-r1
   ##>=app-text/scrollkeeper-0.3.0

   ...

and run (as root) the 'emerge_rsync.sh' script as many times you want! ;-)

It will also present you with what has been changed in package.mask and in 
"world".

Also give a look into the scripts to know a little more - I've minimally 
commented them and they are fairly simple.

I hope that you find this useful. If yes, please tell, and I'll make sure 
that any fixes and improvements that I (or others) make get back to you 
(e.g., by hosting these scripts in my webpage).

Regards,

José Fonseca