Can I write a page template that changes the ATA theme header image and nothing else? So I can have some static pages that use particular header images (for different parts of my site).

I'd like the template to contain as little code as possible, pulling in everything from the ATA default pages.

yoou can use CSS to change the header image and or background image on a per page basis. If you do a forum search, I'm sure you will find the threads