I noticed recently that I use lots of bits of free source code from various places. Stuff like SWFObject or cunitescore or PHPFlashMyAdmin pr AMFPHP or other little bits of eternally updated code that exists on various sites. Problem is, I need to check with those sites once in a while to check for bugfixes and the like.
What if the makers of that code put a little chunk of XML in their header like so. . .
Then you'd have an app that'd scan your project directory for files with this header or, even better, a plugin to a development environment that'd scan the files in a project. And once in a while you could run the app or schedule it as a task or press the "check my internet objects" button in your IDE, and it'd compare your files with the ones in the repositories, pester you if something had changed, let you see the changes in a diff-tool (if it's text), and let you decide if you want to replace the existing version with the new one.
That way keeping your objects updated would be as simple as pressing the "scan c:/documents/projects for changes" button in an app.