Does anyone know of a plug-in or method to use Excel to generate a 'Tag
Cloud' chart / graphic in Excel?

I export database records to Excel for detailed analysis using pivot tables,
and I'd love to have a way to turn entries in a 'Keyword' field into a tag
cloud. Basically this:
- Read the contents of a column (field) marked Keyword, in a spreadsheet,
where each cell can contain more than one keyword
- generate a list of all unique key words (strings) that appear in the cells
- count how many times each unique keyword appears in the field
- create a graphic that shows all the keywords, with font sizes increasing
with increasing frequency of occurrence in the spreadsheet.

I believe that this would be a handy tool for generating graphics for
discussions, reports, etc.