A really useful tool that was demonstrated at MacSysAdmin 2013 (see Greg Neagle's presentation on managing updates) is autopkg: http://autopkg.github.io/autopkg/
I'd like to see if this functionality can be built into Composer, so I've posted a feature request outlining what I'd like to see. Comments welcomed.
Link to feature request: https://jamfnation.jamfsoftware.com/featureRequest.html?id=1440