The caching part looks really interesting -- have you considered adding support for more fine-grained caching control, such as respecting etags and last-modified times?
Yup! That's on the todo list. Auto-caching, as I'm calling it, would figure out a how long to cache something for and then be able to later on use HEAD to check if the url in question has changed.
That cache time could be as long as 5 seconds, so that Templar is checking pretty often if the upstream has changed.
Thanks for sharing this!