The Black Library website has samples of the artwork from two upcoming 40K novels.
From their website:
How good do these look? BL artists, Jon Sullivan and Hardy Fowler are clearly at the top of their game at the moment. These two pieces relate to products we haven’t actually announced yet, but it seems criminal to keep them under wraps any longer. The Dark Angel is the work of Mr Sullivan and the Raven Guard Scout is the work of Mr Fowler. I think they both deserve a round of applause. And maybe even some high quality biscuits.