The attached list contains packages that were found to have dev-libs/boost in RDEPEND, but don't install either any binary that links against boost libs nor any files that include boost headers. That means it uses boost header-only libraries at compile time only. The tracker bug contains the emerge --info of the test system.
Created attachment 210152 [details] kde-wrong-boost-rdepend
What's the status of this with recent KDE (4.3.5, 4.4.2)?
We've reworked kdepim dependencies (boost was being pulled in eclass that's why your list contains whole kdepim) so it's unlikely an issue anymore.
Closing per comment 3, reopen if it is still an issue, thanks