Find maximum value across a row

Hi,

I am wondering if there is a tool that will look at a row, find the maximum value from column A, B, or C and then update column D with the name of the highest-ranked column. I could implement this as a cursor in Python but I would like to know if there is a set-based method that could be performed with ArcGIS Desktop (I have previously done this in SQL Server, but want to keep the requirements to a minimum).

At this stage the data is a polygon derived from an intersect, but it could also be modelled as a series of rasters.

Thanks,

Matt