I haven't used ALSA in about a decade and I never saw the need for Pulse as OSS does everything I want. Seems Ubuntu devs do use Pulse though as with it removed you lose your system sounds.
To get them back you need a recent version of libcanberra and this is how to do it.
Assuming you have already cleansed ALSA & Pulse from your box AND added gstreamer AND enabled sounds using the old gnome-sound-preferences as detailed under Google and as per the Wiki then all you need to do is to get and compile libcanberra-0.18
Get it from the here.
you will probably need to add some libraries to correctly compile the code,
and maybe some others but error codes will point you in the right direction if you lack anything. Unwrap libcanberra with
sudo apt-get install libvorbis-1.2.3 libtool libvorbisfile3
tar xvzf libcanberra-0.18.tar.gz
that puts the new library in /usr/local/lib although that can be configured to put it straight in /usr/lib instead if you want.
./configure --disable-alsa --disable--pulse --enable-gstreamer
sudo make install
log out and you should be done.
sudo mv libcanberra-0.15 libcanberra-0.15-OLD
sudo cp libcan* /usr/lib/ -r
sudo ln -s libcanberra-0.18 libcanberra-0.15