I already have to make the packages for the original installs, update the packages regularly, and maintain polices for new installs. Its just a few more clicks to make a "force" policy in addition to my "on demand" policy. I scope the "force policy" to devices with apps that our not current and update it every 6 months or so.
I know its not automatization, but this is what I do for our some 300 apps I maintain. Its literally just copy the policy when I update the package and set a force trigger with a smart group. JAMFs patch management kinda sucks, and you need the Policies for new installs anyway.
