Few people seem to use it directly. Most people are writing production systems with the Tornadio2 wrapper (https://github.com/MrJoes/tornadio2) or sockjs-tornado (https://github.com/MrJoes/sockjs-tornado)

Load balancing is usually done with HAProxy I hear.

I'm currently creating a product using the Tornadio2 wrapper. The developer Serge is actively developing, and is very helpful.

HAProxy is often used for load balancing websockets as it supports tcp proxies.

There is a tcp module for nginx that can be compiled in at https://github.com/yaoweibin/nginx_tcp_proxy_module

I will second this. I originally deployed chatfor.us with tornadio and then moved to sockjs-tornado and found both extremely easy to implement. I use ha proxy for that app. Unscatter.com doesn't use web sockets and I use nginx as the proxy load balancer for it.

SockJS-tornado can be hosted via HAProxy. If you don't need native websockets, sockjs will work behind any sticky-sessions-aware loadbalancer using comet fallbacks.