Why don't modules support "external locations"?

Is there any reason that modules do not support “external locations”? Or, do they and I just have not found the right settings to use them?

I am still going through this process of trying to override views and layouts (at a minimum) with a separate “template”. Using the external locations in the base application, I have it working so that it will check the “template” folder structure for a view and if it does not exist, check the base folder structure.

However, because I have not been able to find support for external locations in a module, this process of checking one location before using the default view/layout does not seem possible without a lot of customization of the core.

I can go in and customize the Renderer and the view/layout discovery process to include some additional paths, but this does not solve being able to overload a handler or other object.

Am I missing something (hopefully)?