[pron]

Using Grizzly/Netty as the core comm component seems like a good idea. Jersey integrates will with Grizzly, I think.

Dropwizard packages together Jersey on top of Jetty with good monitoring, but doesn't take care of other stuff like multicast. Nothing prevents you from adding Netty/Grizzly into the mix, though.

Actually, the modularity, composability and cross-cutting concerns you mention suggest Spring – not lightweight by any means, but neither are your requirements :)

I think you can even use Jersey with Spring: http://www.infoq.com/articles/springmvc_jsx-rs