If you can control two different pedestrians on the PS2 version, but not split screen. I waived it off as a performance issue with the PS2, and was hopeful that they might add it on XBOX and PC. I was surprised that Rockstar did not do this, especially on XBOX. Didn't even Doom 3 get a split screen mode on XBOX?
Why not make a 2 player or 4 player split screen multiplayer for PC San An? I'd be happy with a broadband online-multiplayer game either way, but the other half that don't have broadband wouldn't be able to take advantage of your work.
I just tend to think that an offline multiplayer mode, using the original icons if need be, would be the single greatest mod for GTA... if you have a good tv. Of course support for more than one USB controller would be required... either that or get 4 identical controllers and tell the game to give them all the same key bindings.
I'm assuming that your online multiplayer mod will have LAN support. My only request is that you work in some sort of anti-cheating system and get damage support for aircraft.