Arkadyzja has been one of the emerging fighting game platforms alongside something like Fightcade, and it's quickly shaping up into something very interesting for those who are interested in the 3D era of fighting games.
The latest release is a public beta that features PS2 netplay that supports up to 8 players through the multitap.
You're going to have to settle for delay based netcode when it comes to PS2 games overall, but that's as good as it gets without people having to dig into the guts of individual games to figure out a rollback solution.

