Upgrade to xl2007.

Or use an event macro that replaces the conditional formatting???

If CF'ing numerics, John MCGrimpsey shows how to get up to 6 different font
colors.

http://www.mcgimpsey.com/excel/conditional6.html

For anything else you are forced to use event code similar to this.

Option Compare Text
Private Sub Worksheet_Change(ByVal Target As Range)
Dim Num As Long
Dim rng As Range
Dim vRngInput As Variant
   Set vRngInput = Intersect(Target, Range("D:D"))
   If vRngInput Is Nothing Then Exit Sub
       On Error GoTo endit
   Application.EnableEvents = False
   For Each rng In vRngInput
   'Determine the color
       Select Case rng.Value
       Case Is = "A": Num = 10    'green
       Case Is = "B": Num = 1    'black
       Case Is = "C": Num = 5    'blue
       Case Is = "D": Num = 7    'magenta
       Case Is = "E": Num = 46    'orange
       Case Is = "F": Num = 3       'red
       End Select
   'Apply the color
   rng.Interior.ColorIndex = Num
   Next rng
endit:
       Application.EnableEvents = True
End Sub

Gord Dibben  MS Excel MVP