>>> --tree implies --pretend... adding --pretend to options.
These are the packages that I would merge, in reverse order:
Calculating dependencies ... ...done!
[ebuild N ] kde-base/kde-3.4.3
[ebuild N ] kde-base/kdeadmin-3.4.3
[ebuild N ] sys-process/vixie-cron-4.1-r8
[ebuild N ] sys-process/cronbase-0.3.2
[ebuild N ] kde-base/kdeedu-3.4.3-r10
[ebuild N ] kde-base/kdeaddons-3.4.3
[ebuild N ] kde-base/kdemultimedia-3.4.3
[ebuild N ] media-plugins/gst-plugins-mad-0.8.11
[ebuild N ] media-libs/libid3tag-0.15.1b
[ebuild N ] media-libs/libmad-0.15.1b
[ebuild N ] media-sound/cdparanoia-3.9.8-r2
[ebuild N ] media-libs/xine-lib-1.1.1-r3
[ebuild N ] media-libs/libdvdcss-1.2.9
[ebuild N ] gnome-base/gnome-vfs-2.12.2
[ebuild N ] gnome-base/libbonobo-2.10.1
[ebuild N ] gnome-base/gnome-mime-data-2.4.2
[ebuild N ] media-libs/taglib-1.4
[ebuild N ] media-libs/libsamplerate-0.1.1-r1
[ebuild N ] sci-libs/fftw-3.0.1-r2
[ebuild N ] media-plugins/gst-plugins-esd-0.8.11
[ebuild N ] media-plugins/gst-plugins-alsa-0.8.11
[ebuild N ] media-libs/gst-plugins-0.8.11
[ebuild N ] media-libs/gstreamer-0.8.11
[ebuild N ] gnome-base/gconf-2.12.1
[ebuild N ] gnome-base/orbit-2.12.4
[ebuild N ] dev-libs/libIDL-0.8.6
[ebuild N ] dev-libs/liboil-0.3.6
[ebuild N ] media-sound/lame-3.96.1
[ebuild N ] media-libs/libsdl-1.2.8-r1
[ebuild N ] media-libs/libggi-2.0.1-r1
[ebuild N ] media-libs/libgii-0.8.1
[ebuild N ] kde-base/kdewebdev-3.4.3-r1
[ebuild N ] kde-base/kdeutils-3.4.3-r1
[ebuild N ] kde-base/kdetoys-3.4.3
[ebuild N ] kde-base/kdegraphics-3.4.3-r3
[ebuild N ] media-libs/imlib-1.9.14-r3
[ebuild N ] media-libs/giflib-4.1.4
[ebuild N ] dev-libs/fribidi-0.10.4
[ebuild N ] kde-base/kdenetwork-3.4.3
[ebuild N ] dev-perl/IO-Socket-SSL-0.96
[ebuild N ] dev-perl/Net-SSLeay-1.25
[ebuild N ] app-crypt/qca-tls-1.0-r2
[ebuild N ] app-crypt/qca-1.0-r2
[ebuild N ] kde-base/kdeartwork-3.4.3
[ebuild N ] kde-base/kdegames-3.4.3
[ebuild N ] kde-base/kdepim-3.4.3
[ebuild N ] app-crypt/gpgme-1.0.2
[ebuild N ] dev-libs/pth-1.4.0
[ebuild N ] app-crypt/gnupg-1.4.2-r3
[ebuild N ] media-gfx/xloadimage-4.1-r4
[ebuild N ] dev-libs/libusb-0.1.10a
[ebuild N ] mail-mta/ssmtp-2.61
[ebuild N ] net-mail/mailbase-1
[ebuild N ] kde-base/kdebase-3.4.3-r1
[ebuild N ] sys-apps/eject-2.0.13-r2
[ebuild N ] kde-base/kdebase-pam-6
[ebuild N ] kde-base/kdelibs-3.4.3-r1
[ebuild N ] media-libs/libart_lgpl-2.3.17
[ebuild N ] dev-libs/libxslt-1.1.15
[ebuild N ] dev-libs/libgcrypt-1.2.1
[ebuild N ] dev-libs/libgpg-error-1.0-r1
[ebuild N ] dev-libs/libpcre-6.3
[ebuild N ] app-admin/fam-2.7.0-r4
[ebuild N ] net-nds/portmap-5b-r9
[ebuild N ] x11-libs/qt-3.3.4-r8
[ebuild N ] media-libs/nas-1.7-r1
[ebuild N ] media-libs/libmng-1.0.8-r1
[ebuild N ] media-libs/lcms-1.13-r1
[ebuild N ] net-dns/libidn-0.5.15
[ebuild N ] net-print/cups-1.1.23-r7
[ebuild N ] app-text/poppler-0.4.3-r4