I'm looking at the 'Puma' section in Jesse Storimer's book "Working With TCP Sockets" and that seems to be the general idea behind it... uses a thread pool for concurrency, monitors persistent connections with an evented reactor.

I'm not affiliated with the author, but this was such a nice book to get an intro to webservers and their architectures/tradeoffs from.

Really fueled my love of sockets :)