For OSOL only, 32-bit only, with crashes: KDE 4.2.2 libs and base can be built from the specfiles in the kde4-specs-42 Mercurial repo. Just in time for the hard feature freeze for KDE 4.3, too. The patches and base-specs are probably the interesting bits there, long-term, as I'm beginning to doubt that the approach taken for "pure" specfiles in that repo is the right one (the one in kde4-specs-dev might be convoluted, but it seems to be more stable than what I've tried now).
[ade]
