Has anyone tried the Dri Ducks Poncho? Cabelas has some and are they the same thing others
have used? How big are they? Would they be good trail raingear for scouts?

Yes they are a good poncho. They are lightweight and don't cost much (~$13). You can order them directly from frogtoggs and get a bulk discount. They are self storing. The material isn't as strong as a 70d pu-coated nylon poncho, but it will hold up better than the disposable plastic emergency rain jackets.

I carry one a lot and have used it in heavy storms - it works.