LabEscape makes a product called “HeatMap Explorer” for converting Excel spreadsheets and SQL databses into interactive HeatMaps for BI uses.  The software to create the maps is a Windows-only package, but offers a web-based Java viewer.  One of the demonstrations on their website is an impressive visualization of Car Fuel Economy that combines a lot of data into a small easily managed space.

A heat map where each rectangle, or cell, represents a car. The size of each car corresponds to its annual fuel cost and the color corresponds the highway miles per gallon. Cars are grouped first by type of car, then by make. Green and blue cars get good mileages, while yellow and red cars get bad mileage. Use the search box above the heat map to search for a specific make or model.

They also have a demonstration of a project portfolio healmap.  They offer a 14-day free trial of the software, which can be purchased for prices starting at $1,295/user.

via Lab Escape: Learning Center > Overview.