I do a lot of responsive design work where I have my master page templates on one page and then usually have a complete rollout page where I show content mockups etc. I normally have to duplicate my master templates to show them on this rollout page which is fine - until there are change requests then it becomes problematic to remember to update the duplicated page templates.
I propose we have a way of mirroring a frame so that if there are changes on the master, they are reflected elsewhere in the file. You may be thinking well why dont you just create a component as thats the same thing right? Well not really as its effectively not a component, its a page template !
I see a plugin exists already that is along similar lines but I think this should still be a native feature as its so beneficial for keeping a single source of truth in your work.