I use a Demb Flip It! Reflector http://www.dembflashproducts.com/flipit/ and it works really well indoors and outdoors. You can change the angle of the reflective screen from about 60 degrees forward to flipping it backwards out of the way. I know you stated you'll be using flash mostly outdoors but the Flip It! really shines indoors when you use it in combination with bouncing off of a ceiling. Check out the gallery for various examples people having used it.