Just an idea, could the config file be split into two, one for (very) site specific info, license, permalink url, region etc and one for the info probably not likely to be different between installations.
Occasionally the gentlemen sneak a new config parameter in and that, if your managing multiple sites means a bit of work. Usually we have upgrades down to a core repo deployed across all installations, which is a major time saver (we do the same with another CMS) a standard config file we could include by default would really help.
Disclaimer: I am lazy.