Belated welcome to the site, PriusMatty!
I think you'll find that there aren't a lot of aftermarket fuel economy mods, and the ones that are available tend to have an impossibly long payback time (if that's your motivation).
Most folks around here tend to fabricate their own parts, and the work ranges from professional to, well, mine.
How are your fabrication skills? What's your philosophical position on form vs. function? How much do you care what the end result looks like?