I think this style of painting can be taught just like any other one.
The secret is in breaking with standard palettes, i.e. go away from "painting skin with skin tones" and move to greys, violets, pale greens etc.
As was already mentioned, you also need to work with a lot of washes and glazes / ink work to get the "stained" look right.
Try to google "INQ28", there are some great projects hidden behind that game, and it will lead you to some great blogs and tips for painting.
Some useful links:
Jakob Rune Nielsen ,
INQ28
I assume that since you posted the spikeyratpack tutorial, you already checked out punkmoth's
thread?
EDIT:
btw, the
WD has/had an article series called "blanchitsu" which is/was all about realizing Blanches illustrations into miniatures, including painting tips. If you google that, you will find lots of great painting projects.