We use Greg Neagle's http://managingosx.wordpress.com/2012/07/25/son-of-installlion-pkg/ to create our OS installers. We have a static group which will cache the installer and update inventory via every5 policy and a smart group triggered off the cached installer that enables a Self service policy. Upside to this is that we can add handy lil extras in the installer.

Only downside is uid<500 management users get blasted by the install. Not too hard to fix with the ability to create a package which will recreate as necessary.

Tested on in-place upgrades from 10.6.8 and 10.7.x.

Thanks for the link. I created an installer package using this tool. I had one policy cache the package and a self service policy run the installer. On the first machine I tested, nothing happened other than creating the directory with the installation resources, etc. I was under the impression that a post flight script would restart the machine. After about 10 minutes, I manually restarted the machine and it re-booted into the ML installer and installed successfully. On the second machine, same policies (cache then Self Service). I set a reboot delay of one minute but it didn't end up booting to the installer, just back to the original OS. Is there some kind of delay associated with the post flight I should be aware of?

I tend to walk away after starting the policy. It is set to install the update, then runs /sbin/reboot on the advanced tab.

Okay, figured it out. On the reboot portion of the policy, I had to select Currently Selected Startup Disk (No Bless).