We are starting to use PDF Portfolios as part of our multi-media publication, and struggled with how to find or create a more custom-look, branded portfolio. I'm sure we're not the only ones who didn't want to learn Flex just to be able to do this. That's why I was really excited to see Chris Converse's video tutorial here, which somehow I had overlooked before:
http://www.acrobatusers.com/tutorials/modifying-pdf-portfolio-navigator
Moving at a (very) brisk pace, Chris walks you through detailed but not difficult steps to modify the art and settings inside a specially created .nav file, which can be downloaded free (thanks, Chris, Adobe, and everyone involved!)
If you've wanted better file folder icons, or a nicer background with your logo, or whatever...this is just one format (the revolving presenter) but it shines a light into the inner workings of the PDF Porfolios.
Thea
Yes, creating a new navigator from scratch is currently far from trivial, but be patient. Portfolios are still in diapers, but growing up fast.