I was aware of what he was asking, I was just making a suggestion of an
alternate approach that in the next version of Excel, that will be out later
this year, offers far more possibilities. Rather than one conditional format
per cell you can have many.

As to the multi colouring, I can only see that being done through VBA. The
actual logic on what character changes to what colour is not that hard. The
actual colour change  can be done with

ActiveCell.Characters(Start:=1, Length:=1).Font.ColorIndex = 12
ActiveCell.Characters(Start:=2, Length:=1).Font.ColorIndex = 17
ActiveCell.Characters(Start:=3, Length:=1).Font.ColorIndex = 4
ActiveCell.Characters(Start:=4, Length:=1).Font.ColorIndex = 46