I regulary visit http://www.sonsofthestorm.com/ as I find that they do have some nice artworks.

Just saw that the "Sons of the Storm" have their 7th son, codename Red Knuckle.

I checked his personal artwork and found a few pictures from Warmachine, but also Warhammer Fantasy and Warhammer 40K with the logo "MG" attached to it. Some of them I knew Mark Gibbons painted (if I remeber correctly).

I thought Mark returned to GW, did he leave or was he just freelancing for GW.
I really don't know if "Sons of the Storm" is something contract binding, but he sure is doing some artworks for Blizzard now.