Kind of related, I recently made a similar style of visualisation for 99designs.com - http://a.tiles.mapbox.com/v3/dhotson.d2013/page.html

Once I got the data into PostGIS and aggregated into hexes (slightly harder than it sounds) it wasn't that big a deal to visualise using Tilemill and MapBox.

I haven't read the nanocubes paper yet, but it sounds much much faster than my approach using PostGIS. It took me many hours to import and process tens of millions of points in my visualisation. It'd be great to be able to turn something like this around in <10 mins.

Would this nanocubes approach work with hexes? (they look cooler IMO)

Offtopic: After all this, all I can think about—is making a Settlers of Catan MMO. ;-)