Phew, done!
I extended the time to an hour and a half so I had time to work on the hair as well. An hour for the face and 30 minutes for the hair. I like the way it turned out, but it's definatley not good enough to be released as a skin
I think that the eyes are it's weakest element, which is annoying since they give a skin a lot of character... need to work on making eyes more realistic! I'd like to try and but a lot more effort into the hair next time as well, I may try doing just a 'hair test' next time, using an entire hour working on just the hair - this would also let me create an alpha map for the hair to make it look a lot better, I mean who has hair clumps into triangles at the tips like this guy's?
Anyway, here's the finished skin:
Here's the final product and the texture itself (resized from 1024x1024 to 256x256).
Here's the skin as it progresses.
old_man_funk