Y'all are making this too damn hard. A simple roll cast can work when needing to change angles in moving water (throwing back across the river after letting the fly swing downstream), but direction changes over 30 degrees can be tough.
I think the double spey is most useful for the situation the original post described. Its a little tricky to learn, but you'll find yourself doing it as often as possible once you get it just for the fun of it. Here's the two most important things to remeber: always have at least your fly (if not some leader as well) touching the water before delivering the forward cast, and do not cast over your leader. (doing the latter generally causes tangles.
You may find it easier to use your non-rod hand to the butt of the rod to add a little more snap to your stroke. I frequently use the technique with my 9' 4wt and can throw 70' with little backcast room.