Hi there. I'd like to throw my hat in on this one.

Here's a recent map that shows my take on a semi-realistic painterly style. I hope it's close to what you're after:
Click image for larger version. 

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This was published in Open Design's Dwarves of the Ironcrags Gazeteer and Halls of the Mountain King and is rights reserved (in contrast to the CC license in my sig).

You can find more maps on my website:

www.fantasticmaps.com

There's a full world map here:
http://www.fantasticmaps.com/Gallery...rldOnACog.html
though that was created for a much larger scale print than the one you are discussing.

You can contact me at jonathan@fantasticmaps.com. I look forward to hearing more about the project.