Hello Brent,
I realize that you posted this some time ago but I just came across it. To address your original question, as a LA I felt that becoming accredited in Neighborhood Development was by far the most appropriate, and the most useful, in terms of our professional scope. While not perfect, it is a way to qualify and quantify “sustainable.” It is expensive in terms of both money and time invested but it is important to remember that LEED certified developments (buildings) have a higher and faster resale and, use less natural resources including, water and land–two things in finite supply. Possibly, the USGBC just needs some good old fashion competition to force them to streamline the cost and process. It will come.