Did some testing with my pointclouder python script i wrote for Nuke, attatching it to a CSV reader i loaded in some examples posted on the Nuke user forums: http://forums.thefoundry.co.uk/phpBB2/viewtopic.php?t=6982&postdays=0&postorder=asc&start=0 , sadly the data did only include luminance and not color data, but it still gives quite a good readout.
5 million points is a bit much to work with but filtering off 80% of the points still give a great result.