I installed Vidalinux on one of my desktops to give a Gentoo clone a try. I want KDE since I'm really not a fan of Gnome so I tried 'emerge kde' and it gave me about 40 packages and that's it, looking through porthole there are still LOTS of packages that weren't installed.

So, how do I tell it to install the rest?

what dd it not install that you need?? try emerge --search kde and see what you get back.. I wouldn't even bother using porthole.

If you want to use Gentoo.. you can convert VidaLinux to complete Gentoo...

emerge gentoo-dev-sources (for compiling your kernel) or emerge genkernel then genkernel all to compile and install it. then you can just change the /boot/grub.conf

next, simply "emerge -e system" and go to bed..that will rebuild the whole base system. When you get up, set your USE flags in /etc/make.conf(if you want to change them, if not, leave it alone) then "emerge --update --deep --newuse world" and let it rebuild your world.. oh.. and also emerge grub and install the gentoo grub so that you don't still have the VLOS grub screen.. I did all this with my notebook, and don't have the slightest bit of anything relating to Vidalinux now...

for a base kde, try to just emerge kdebase, which technically only needs arts, qt, kdelibs and kdebase for a minimal kde desktop. then just add from there. of course, portage will try to add in an extra 15-20 packages you "need" with the above....