> .plan: 
> * Play around with Portage, get to know it properly
> * Select the packages that are to be installed in the base 'secure' system
> * Sort out the differences between the standard Gentoo packages and my packages
> * Make .ebuild files for the packages that are missing (libsafe, LIDS etc.)

Makes good sense, especially the first item!  If you give us some
examples of how your secure packages will differ from our standard
ebuilds, once you get there, we can probably help.  

> And how do you think the whole thing should be implemented? Will it be with a
> USE variable? Would I then have to alter every one of the .ebuild files
> available to respect the USE variable?

Use variables (along with a unique profile) are almost certainly the
right way to go about it.  Only ebuilds that need different
functionality would then need the new USE variable.  Presumably the
KDE/GNOME ebuilds, for example, should never need to be touched.

> I'm thinking I could solve the problem of which packages to include by having a
> 'use secure (or whatever) && die "This package is not supported in the secure
> distro [blah blah]"' directive in the packages that won't be included (like
> XFree86, KDE, Gnome, etc.).

Nah.  You set up the default packages to install in your
profile/packages file.  If people want to install unsupported packages
you can either just let them do so, or I'm sure that Drobbins can figure
out a reasonable way of making sure that if /etc/make.profile points to
your secure distribution then only those packages in
/etc/make.profile/packages would be allowed by portage.

Best,
g2boojum
-- 
___________________________________________________________________
|     Grant Goodyear                  |  The Secrets of Physics:   |
|     Dept. of Chemistry - Clemson U  |1. Add zero.                |
|     Clemson, SC  29634              |2. Multiply by one.         |
|-------------------------------------|3. Expand in a Taylor series|
|e-mail: goodyea@clemson.edu          |4. Integrate by parts.      |
|www:g2.ces.clemson.edu/~grant        |5. Fourier transform.       |
|                                     |6. Add auxiliary variables  |
|_____________________________________|____________________________|