Normally, I'd recommend that you visit the 3D Comic Collective. They have a lot of capes to choose from, although they're mostly superhero-oriented. I can't recall if any come with hoods. In any event, the site is currently down, due to technical difficulties.

You can find a nice, free cape over at Gloria Gast's Poser Junction.

The cape doesn't have a hood, but perhaps you could improvise with thip's Mike Mantle (available here in Free Stuff), which does.