Request: Pass Information to Header, Footer, Sidebar

It would be wonderful if the get_header, get_footer, and other include functions would accept an extra optional parameter of some dataset (array or object) so that you could pass different data to the included section when inserting it.

This way you could have, for example, a few slight variations of the header without having to manage and update a number of different files, or have a bit of content varying between pages, posts, category pages, etc..

I know there are plenty of other ways to accomplish the same results but this would be a great feature in some cases, and should be easy to implement.