WAS, it's great to hear that your videos are getting more views.
In answer to your question above, yes, we're very interesting in developing additional tutorials and content that highlight different aspects of Terragen, or of specific interest such as the ground-level distribution or even more realistic surfaces as you mentioned.
I encourage everyone to submit any ideas for topics that you're interested in learning more about, and we'll start looking into them to determine the best way to explore them in more detail, whether it's a video or wiki page tutorial.
Thanks!