>Re-arranging the main sail sheeting will probably force the sailor to reside farther aft. I also image such an arrangement makes sail handling and steering a royal pain.

Not so... I repositioned the mainsheet at the end of the boom on my M15 and added a boom vang. With the aid of a Forespar adjustable tiller extension, I sit forward in the cockpit most of the time. Sometimes I even sit on the bridge deck with my legs dangling through the companionway into the cabin. Of course, this seating position is possible only if you remove of all the mainsheet tackle from the bridge deck.