I know, it's quite difficult to find decent comic tutorials. The curves tutorial is useful when you want to make icons and the like based on a comic, but it isn't a comic tutorial per se. You know one that explains, for instance, how to make a speech bubble in Gimp or Inkscape. But I think you should definitely make that tutorial you're talking about, even if it's not the kind of tutorial I'd in mind. I'm sure other people would most definitely be interested, and also might come in handy for me at a later point :)