Okay, after many iterations and changes, I've finally packaged up the Meld URL Interceptor for the Mura CMS into a functional plugin. This is mainly a development tool, to be sure, but I'm sure the creative out there will find many uses for it. Perhaps best of all, it's free (GPL 2 licensed)!
Meld URL Interceptor offers a few very significant benefits. First, they make URLs "friendly" to both human eyes and search engines. Second, they hide your variable architecture from unfriendly eyes, making it harder to crack your site. Third, they incorporate validation at a very early stage (again, helping to foil the ne'er-do-wells). Finally, they are a very efficient method of packaging variables for your Mura-integrated applications.