Here’s a good thing, those nice Gentoo folks are going to create ebuilds for the various components of KDE, migrating away from the monolithic, all-or-nothing ebuilds for kdebase and kdepim to packages for things like kdebase-kioslaves and kopete. The monolithic ebuilds will be maintained for 3.4, but for KDE 4.0 and later there will only be the split ones.

For the details see the Gentoo KDE Split Ebuilds HOWTO.