This library sounds very useful.

HTML-Table seems to be a popular module for building HTML tables. Does it make sense to sublcass it and make your module into HTML::Table::AutoFormatted?

Are the red, ylw and grn formatting routines providing a way to set priority for the routine? So if conditions would call for both red and grn rules to apply, only the red is used? This is confusing. Why not either pass in a priority number? Or use "high", "low" and "standard" as your priority names. The color thing is confusing.