I'd like to develop a plugin that allows me to have custom user pages.  I really like the way the author archive template handles the URL: /author/username. I don't want to rewrite the `author_base` as I'd like to keep that functionality in place untouched. 

I'd like to replicate that clean URL layout in my plugin, so that when a user goes to /users/username it will go to my custom template.  I'd like to know if anyone has examples of how to properly parse the username from the URL so that I can lookup the user's data from the plugin and display my template.