I haven't tried these out, but I'm really impressed at how well you overcame the problems with self-made DEMs. I would have never thought of using this technique to make them look more weathered and realistic, but now that I've seen it, I'll be trying it as soon as I can. I just hope that adapting them to a more rigid and defined region of mountains works well (unless I'm mistaken you did both this and your actual map from scratch), but either way having DEMs that already look good and aren't messed up by countless alterations. will be awesome.
Bravo, and have some rep. Can't wait to see part two.