Vertex paint mode shaded view in cycles When in vertex paint mode - the object being painted is displayed as shadeless.
This makes painting on a complex model difficult - as you cannot really see what you are doing.
You can use dirty vertex paint to make the geometry visible - but this is not ideal.

This is improved in the Blender render textured view using multitexture shading which gives you a shaded view.

In cycles the object remains shadeless in both shaded and textured mode.

Can this be shaded so it is not shadeless when using cycles?
This was changed in 2.71, now solid view is displayed with shading, and wireframe view is shadeless: