Proven and Scalable Comet Server

What is the most proven, scalable comet server solution out there that can handle up to 100.000 real-life connections per node using HTTP streaming (not long-pol开发者_如何学JAVAl)? It must be a free, preferably open-source project.

We've already tried Meteor (Perl), with no success. Meteor was able to scale just up to 20.000 connections per node.

We are looking right now at these options: APE (C++), Orbited (Python), Grizzly (Glassfish), Cometd (Jetty).

Any big success stories with any of these?