Hello Sebastian, this sounds like a very interesting project! I didn't do any commissioned maps yet so for me this would be a great opportunity. I'm not sure if my work has the professional-quality you require but you can look at deviant art (link below) to check for yourself. If the style you're aiming at doesn't match any of my work maybe you can point out some references so I (and other members) can see if I could create a map in that style. cheers!