Flat vertex painting, or face painting? Vertex painting is far too soft for me:


I'm looking to paint something more like this (not exact, but close enough):



Instead of smooth interpolation, color interpolation should be done on a per-face basis and not smoothed between faces. And if possible I would like to paint faces, not vertexes.
Select faces in Edit mode
Switch to Vertex Paint mode and press Face selection masking for painting button (3D view -> bottom panel -> button with cube icon (next to layers selection)

Press ShiftK to fill selected face with the selected color.




This way, you can also normally vertex paint your model but painting will be limited to selected faces only.