Artrage 3 is a really good sketch tool. Was trying out the demo today
www.artrage.com

Fun project illustrating a story for a friend.

Background model in Solidworks, and quads exported from moi3d.
Blender 3d, for character modeling, fluid sim and rigging. Maxwell Render for image above.
Needs further work in Photoshop to fix artifacts here and there.

Thanks to Andrew Price from Blenderguru.com for invaluable tuts as well providing .blend files that I could dissect and use for the image above.