You can make each one into a custom Page Template, and either add the style block directly in the template, or conditionally load a stylesheet based on which template is in use. This will let you still use the editor to change the content of the page, but involves a lot of “one-off” page management.
I ran across this post that describes a way of using WordPress themes in pages outside the WP install itself. It may be useful to you: http://seb.so/adventures-in-wordpress/.