I have a customer who wants to do a directory website. He is planning to sell one page websites to small businesses. He wants three rotating banners for each of their sites. There may end up being several hundred if he is successful.

Using Juggledad's code:

body.page-id-2 div#imagecontainer {
background-image: url('http://yourdomain.com/wordpress/wp-content/hdr_images/page_2.jpg') !important;
}

I can see having a special header for one page. Will it work for more than one image? i.s.
body.page-id-2 div#imagecontainer {
background-image: url('http://yourdomain.com/wordpress/wp-content/hdr_images/page_2.jpg, http://yourdomain.com/wordpress/wp-c...es/page_2a.jpg, http://yourdomain.com/wordpress/wp-c...es/page_2b.jpg') !important;
}

I can see the HTML/CSS file becoming enormous!

the rotating headers are done in a jscript so you would have to do some coding with it.

I would suggest looking at some of the header image plugins and put in a widget area in the header in place of the %image. You might find one that will do what you want. 'cimy header image rotator' is one 'dynamic headers' is another, though I don't know if they will do what you want...

Can you suggest a good thread which talks about how to add a widget to the header area? The information I have been able to find seems very technical and likely beyond my ability.

If I can figure out how to do that and use a dynamic header widget, then I can use the Display Widgets plugin to place it on selected pages.

1) add the following to 'Configure Header Area'

<?php bfa_widget_area('name=Header widget area'); ?>

2) go view the front page of your sie
3) go to dashboard->appearances->widgets you should see your new widget area
4) put the widget you want into it.
Done