Bivariate legends are something that ESRI doesn't do very well. So since we wanted to generate bivariate legends we had to get a little creative. Using some creative ModelBu ilder tools you can create a bivariate legend within your map fairly simply using this model:
Basically using the Fishnet tool you can create your two dimensional grid in a user defined location on the map. Then reclass the two input raster layers using the Slice tool and the number of columns used in the fishnet tool. Next multiply one of the variables by 10 and add the two raster layers together. Convert them to polygons and merge the fishnet and the converted polygons and dissolve.
