I know of several large users of Python + Phusion Passenger. Globo.com, one of the largest media companies in Brazil, runs Django on Phusion Passenger on some of their sites. There was also a site that monitors the forest firefighting progress in California, that runs on Python + Phusion Passenger. Unfortunately I forgot its name.

We run Graphite (a Django app) on Phusion Passenger on our internal servers.

By the way, we open source Node.js support in 4.0.16. Previously it was only available in the Enterprise variant. You can learn more at https://github.com/phusion/passenger/wiki/Node.js