Remember this feather I coloured years ago with Inktense? Great properties, you draw onto the fabric, gently wet it, the colour intensifies, then let it dry, then it is stable. (some of the colour are better than others)
Now they are doing Inktense in blocks (blocks might be a little exageration but much more pigment than in the pencils). I think this will make much easier for larger areas and to avoid the pencil lines.