i also addressed a few api issues in the new kpassworddialog (e.g. remember to always make constructors that have defaults for all their parameters explicit; a showErrorMessage() method; a method to allow subclasses to check a password before the dialog accept()s); addCommentLine() actually adds lines rather than just show the first one, etc) .. i also fixed a few issues in kdelibs/kdesu which should resolve issues like it not saying "put your password in" when using sudo.
i also stumbled upon a little known configuration option in the process: you can define whether you use sudo or su by putting something like this in a config file (kdeglobals recommended):
i worked with el and jan on the usability of the new dialog and i hope to come out of this process with some guidelines and thoughts for other dialogs in kde4 as well.
but yeah.. no more password matryoshka!!!!!