The Hobie Convertable is a combo of comfort and function AND price that is hard to beat. It also sounds like just what you are looking for. I have raced week long events in that harness and been very comfortable. The ease of in and out in great. Many of the sailors at the last Tiger Worlds were using the convertable w/o the shoulder straps.
Definately a GREAT harness.
Due to a back injury I have been forced to a full harness. But thats another story.
Tom