A new architecture was prototyped, but I haven't seen any new implementations. The idea was to have a common interface for UDP,TCP and IP messages, but this turned out to be fairly complex. UDP implementation was the big thing (to keep things low-latency), but it's not easy.
Really I think the key would be to start with a good UDP datagram layer and go from there. Kinda reiterating previous responses, I hear the SDL network layer is fairly good at that (many deathmatch games ported by Loki