While the cover art for the book has been done by Jon Hodgson of Cubicle 7, the interior artwork in the book is being done up by Peter Frain. While I was somewhat concerned about Peter's artwork, based on what had been posted over in the River of Heaven Kickstarter, I needn't be concerned.
Peter's got a nice blog, 77 Studios, and you can check out his artwork these days. Really stellar stuff, both black & white and colour, and so I can safely say that in my opinion, River of Heaven is in good hands art-wise.
So please, if you haven't checked out the River of Heaven Kickstarter or have been thinking about, do so. Maybe even pledge for the game and increase the chances that we see the book with full colour art! :)