(I work on the same site/problem as author)

We would prefer node did not deal with the https, I actually did a previous blog post showing how performance degraded https://www.sharelatex.com/blog/posts/nodejs_http_vs_https.h....

Options like Ngnix and haproxy without pound/stud are quite recent and we have not gotten around to trying them out.

In regards to clustering, running socket.io in a cluster with redis store is another world of memory leaking pain. Hopefully socket.io 1.0 with engine.io will solve this but its been nearly released for several months now.

I am now starting to question the value of websockets, long polling is a lot simpler in many ways and robust.