Maven plugin for versioning and minifying javascript
Take a look at the yuicompressor-maven-plugin. It can aggregate various js (as well as css) files as well as minify and obfuscate them.
Here's a brand-new Maven plugin that targets this task: http://mojo.codehaus.org/webminifier-maven-plugin/
I've successfully incorporated RequireJS optimization (uses Google Closure compiler + does concatenation) in a Maven environment (for single page JS app). See my question and the follow up answer for details: RequireJS Compilation in Maven project with external JS dependencies
You could probably expand on that to version and archive the minified JS artifacts.