Hmm... I happy with it - for now. I still wish I could figure out how to add more texture to the skin, or make light/shadow look more natural - but hey, there are more attempts to come.
Also, I know that everything might appear too dark - well, my laptop screen can be weird, and I just couldn't bring myself to adjust each layer...
What was used: Wacom Bamboo + GIMP + standard GIMP brushes & some from Project-GimpBC
+ about 4 hours of work.
Sketch can be found here.