[RESOLVED] Where are the header and headinclude templates rendered?

[nerbert]

I'm considering a project that will require modifications to the head and headinclude templates but I don't want to give instructions for editing them, instead I want to create header_alt and headinclude_alt templates and have them rendered instead of the usual ones. This way the product can be turned off and the code will just go back to using the usual templates. I'm hoping there's a hook available where I can change the template rendered for the product.

Or is there a better way of going about this?