I'll throw another input in here... I'm totally agreeing with the guys above about the long belly line and I'm anxious to get one myself. However, what works for me with my steep banks, not even ten feet behind me, and 20-30 foot drop-offs, 5 feet in the water in front of me is a skagit setup. I run and 8/9 deer creek rod and a 600grain skagit flight with a t-14 sink tip and around a 5-6ft leader. My fishing is definitely a bit different than yours and I'm still working at it, but I can cast almost straight across the river with this line with just the tip of my right foot in this water. And as I get better and more comfortable with it, I seem to be able to cast farther and farther.
Now, I think that you will
like the long-belly approach better, but I'm just letting you know what "works" for me when I don't have room for much of a D-loop behind me. The long-belly lines seem a bit more graceful to cast. But, there's my two cents.