BTW, what did you end up doing? Did you build something of your own? Any gotchas you would like to share? I am investigating if Nginx will co-operate with the websocket connections and what will be the price of maintaining live connections to a bunch of clients. I am kind of inclined to build and run my own server...
If you want to build and host your own realtime application take a look at HAProxy (tcp mode in 1.4) for load balancing the incoming websocket connections to your application stack. There has been a lot of success using Node.js with engine.io, socket.io, or take a look at the meta Primus module.
BTW any plans to zero-in on the pricing anytime soon? I saw that for one app you will always keep it free, but it will be nice to know what happens beyond that..
We'd be happy to talk to you further about it and get your feedback.
[1]: http://nombo.io/
I'd like to believe it will make you so efficient, you'll make up ground :)