I just want to share a really cool code snippet that allows you to create page templates for Wordpress independent of a theme. It works by inserting the page template manually into the cache, allowing the template to be used in exactly the same way as a template actually included in the theme.
Everything is open source, of course, and you are welcome to use it for whatever you want (both commercial and non-commercial uses).
It is on Github - Page Templater
If you'd like to say thanks, please donate a couple of rep points - that will be thanks enough!
If you would like to contribute/ask a question, you are more than welcome. Fork the repo and/or tweet me @harribellthomas.
Hope you find this useful!