I haven't heard of it, but I wouldn't even try tbh. I haven't seen one successful execution of Netty in PI, let alone grizzly.
Before you start talking about about a bunch of netty releases. That doesn't make it a successful execution. Packets are constantly being dropped and I havent seen a packet handling system with netty that was as conclusive as it was with Mina. So that just leaves me to speculate at how it would perform with grizzly. (Not very well unless of course, your interested in completely re-writing a large chunk of the framework)
Not to mention that Netty is about as far as you'd need to go anyway in the context of a server holding 2000 connections, Grizzly would over an utter overkill.