* Some people have asked for to be able to make "custom" configurations.
  That is, to be able to manually arrange the colours of the faces, and
  have the program solve itself from that position.

* Some insane individual might want a 4 dimensional version.  This
  could be  achieved by splitting the top level window into 8
  sub-windows, each containing its own cube.  The 8 cubes, would make
  up the `faces' of the 4 dimensional `hyper-cube'.  Thus, any cube
  can be manipulated, but this would automatically  affect 6 of the 7
  other cubes.  For inspiration, see the novel by Abbot E. A., "Flatland.  
  A Romance of Many Dimensions", Basil Blackwell, 1978.