Don't threat me as Ubuntu fan, but in kxstudio jack is made to be a fundament of
entire audio system. Its initial environment - KDE, but functionaly, about which I am
writing, doesn't depend on any DE.
It has script, kxstudio-session-start, which starts entire audio system - jack, alsa
bridge, pulseaudio. Currently it also has support for startup session (requires LADISH,
which already included to LiveDVD). E.g., you may create some configuration, which should
includes, besides other things, a2j, and use it on startup.
Initial LADISH version is 0.2, but in repository also ladish-git (0.3) is available.