FM WarB,
When I load up my three day 156 turn battle on the HPS Gettysburg game I see stone walls all over the place. Look around Cemetry and Culps Hill and work your way all the way down to Little Round Top.
I'm not sure if you are aware of it however, Old Banshee has a Gettysburg Graphics Package and a Gettysburg Map and Weather Mod in which you may be interested in using.
You can find them here:
http://old-banshee.yolasite.com/downloads.php
keif149,
You probably won't see a map editor available to us game owners until the series is complete.