It would be hard with the current capacity of modders to grab inputs.
Right now we can only get Left/Right mouse and can't separate them from other inputs. It might be possible, but unlikely, to get two Naija's moving independently with enough kludging. It would be much harder to allow them to do bursts/abilities and the like. You could probably do some limited stuff, but the work/result ration doesn't make it seem worth it to me.
I've been thinking though. Depending on the level of support for Lua, it might be possible to run another application to open and Socket connection and get some kind of netplay going. If the socket program parsed information to file that could be accessed by the Lua scripts in game. It would STILL be a lot of work though.