I recently had a landscape design plan prepared by Tree House Studios. The owner is a landscape architect and the design was done professionally at a reasonable cost. I don't believe she actually does any install or hardscape work (we are doing the work ourselves) but I seem to recall that she can make those arrangements. I found her name in the local paper and took a chance on hiring her. I was pleased with the results and would definitely use her again.
You can check out the webite at www.tree-housestudios.com