That is a crazy scoring system. I have an article on my website covering this. You can visit it here if you haven't already checked it out:
http://www.idpguru.com/2010/08/2010-idp-return-men.htmlDanieal Manning should be quite valuable. He's going to be the starting SS in Chicago and return kicks along with Johnny Knox. Javier Arenas and Akwisi Owusu-Ansah are sleepers. They won't start on defense, but they should factor into the return game and play in nickel packages on defense.
Revis and Finnegan have done return duties in the past, but I don't expect them to this season. They are too valuable to their respective teams for them to be used on returns.
Alphonso Smith is another guy that could be quite valuable in your league as he may return both kicks and punts and play in the nickel packages on defense.
I hope this helps somewhat. Good IDP return men are hard to find anymore.
Thanks for dropping a line in the forums and don't hesitate to start another discussion. I'm usually pretty good at responding quickly and love talking fantasy football.