kmymoney2 installs into /usr/kde/3.5 instead of into /usr. This means that it is pretty much inaccessible in a KDE4 session. I'm not sure as to the intent of "prefix kde3 misc apps in /usr/kde/3.5 by default" in revision 1.172 of kde-functions.eclass, but general applications should always be installed into /usr. Adding PREFIX="/usr" to the kmymoney ebuilds fixes this.
*** This bug has been marked as a duplicate of bug 270747 ***