Ahh - so, really, just a grid of colored boxes, where you control the color.
I don't have any examples 'exactly' like yours, but here are some similar,
that could probably be adapted ...
http://robslink.com/SAS/democd22/heatmap.htm
http://robslink.com/SAS/democd22/heatmap_info.htm
The technique used in this custom calendar chart could be adapted:
http://robslink.com/SAS/democd22/trend.htm
http://robslink.com/SAS/democd22/trend_info.htm
http://robslink.com/SAS/democd21/emission.htm
http://robslink.com/SAS/democd21/emission_info.htm
A gplot, similar to the sgplot that was posted:
http://robslink.com/SAS/democd10/pltwafer.htm
http://robslink.com/SAS/democd10/pltwafer_info.htm
And, most of these 'wafer maps' could be adapted to a rectangular 'heat map':
http://robslink.com/SAS/democd10/aaaindex.htm
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