Not that I'm making excuses, but painting traditionally on large canvases requires time, space and willingness to live in a mess. I live in a condo and when I attempt to paint, somehow I get paint all over my place, the kitchen, the bathroom, my clothes, floors, the walls....it's a huge mess. There's something to be said about painting in a separate studio where you can go nuts and just leave it like that.
The urge is definately there. Once in awhile, I feel like taking the break from concept art and just letting my brush flow. No purpose, just shape and emotion. Here's one of those urges...