I have been looking into the issue of upstart.  From:

http://upstart.ubuntu.com/

Upstart is an event-based replacement for the /sbin/init daemon which 
handles starting of tasks and services during boot, stopping them during 
shutdown and supervising them while the system is running.

and is therein listed as:

Known Users

     Ubuntu 6.10 and later
     Fedora 9 and later
     Debian (as an option)
     Nokia's Maemo platform
     Palm's WebOS
     Google's Chromium OS
     Google's Chrome OS

Copyright © 2010 Canonical Ltd. Upstart is a trademark of Canonical Ltd.

which date indicates that the above list may be obsolete, and probably 
is obsolete in that upstart appears to be incorporated into EL 6 .

 From the upstart FAQ:

What are the example jobs?

The example jobs are based on the /etc/inittab file found in Ubuntu, and 
thus also Debian. They run the same scripts as the old System-V init 
packages on the same events, using the System-V compatibility tools to 
generate runlevel events.

Why don't the example jobs work on my distribution?

Because every distribution has used System-V init differently, every 
distribution's /etc/inittab file (on which the example jobs are based) 
is different.

You'll need to examine this file from your distribution, compare it 
against the one found in Ubuntu or Debian, and modify the example jobs 
appropriately.

End quotes.  I apologize for my lack of free time to dig up the details 
on upstart in SL 6, but if anyone is familiar with upstart as used in SL 
6, I would appreciate links to the appropriate documentation, any EL 
changes from the Debian/Ubuntu distribution source, and related upstart 
material (a state transition chart would be nice given that upstart is 
event driven).  Replies on upstart off list are invited.

I note that openSUSE has included upstart as of version 11.3 Milestone 
4, but not as default (http://en.wikipedia.org/wiki/Upstart).  A 
colleague and I did a comparison of the boot on an openSUSE machine 
versus a SL 6.1 machine -- otherwise essentially identical hardware 
platforms with very similar application and systems environments -- and 
noted a difference.  As openSUSE evidently does not default to upstart, 
this may explain at least one difference in behavior -- he took mostly 
defaults from openSUSE during the installation phase.

Yasha Karant