It can be done in GIMP. I am working on a Brush that can be used to stroke a path/ selection in GIMP. I could not find any out there so I am making my own. I currently only tested with 4 shapes but plane to have an arrya of about 16 shapes for villiage type settings. The next step to take is to build two more brushes for diff densities and building types... The below is my first test of the new brush. I am only very new to CG so have been trying diff scales and techniques like crazy. I am pretty happy with the way the brush works.
http://www.cartographersguild.com/sh...-Westfall-Vaea
If there is demand I am happy to share the brushes as I go. Is it worth starting a WIP on it? Or can someone post a link to existing resource?