What about dedicating a week or so per game since the games are shorter? As long as it's still within the genre it may keep the conversation flowing and get more people involved. It opens up the accessibility aspect for people.
The main reason I proposed Blade Symphony earlier, while not retro in any way at all, it WOULD allow us to play matches online against each other. As anyone knows, having an opponent to play a fighting game against is half the fun .
I've actually gotten the network play of the PC version of Virtual-ON going over the internet with some basic port forwarding, but that's not a very traditional 'fighting game'. There's also One Must Fall Battlegrounds, though I've heard mixed things about that. Any other 3D fighting games we can easily play online?
There's Windom XP---it's sort of a Virtual On-esque game where the various mechs are avatars/incarnations/something of assorted computer operating systems. I think it has a few different online play options.