Will you have only a single letter in each cell? Is each letter upper
or lower case?
If the answer is yes to both questions, create a formula next to each
element of the row as follows:

assuming your row begins in D1 and ends at L1,
in D2 enter "=Code(D1)+right(D1, len(D1)-1)"
in C2 enter "=max(D2:L2)"
in B2 enter "=match(C2, D2:L2, 0")
in A2 enter "=index(D1:L1,1,B2)

That should retrieve the largest letter/number combo in A2

brakbek, here's an alternate solution.  Copy this code and paste it
into a standard module in your workbook.

Function BIG(myRg As Range)
  Dim Cell As Range, v1 As Double, v2 As Double
  Dim i As Integer, ch As String, f As Double
  v1 = 0
  For Each Cell In myRg
     If Len(Cell) > 0 Then
        f = 100000
        v2 = 0
        For i = 1 To Len(Cell)
           ch = UCase(Mid(Cell, i, 1))
              v2 = v2 + (Asc(ch) * f)
              f = f / 100
        Next i
        If v2 > v1 Then
           v1 = v2
           BIG = Cell
        End If
     End If
  Next
End Function

To use it (say your range of cells is in C7:F7), type this into a cell
=BIG(C7:F7)

James