It's been said before on this and other threads, so I, even as a fairly newb to the board, can repeat it.
It is above and beyond what is possible with the icon framework. Hit points, spawning, NPC pathing, and power triggering were all run from and timed off of the servers. The only reason icon 1.7 has the maps at all is because they were contained in the client, like the costume pieces and certain static NPCs like contacts, so you didn't have to redownload 1-4 gigs of info every single time you logged in. anything more than that relies on the server.
so sadly, whether it's a real game server, or a program running directly on your PC, it would require a complete working server analogue to make any form of combat happen.
whether or not someone is working on that...
I don't know nothin bout nothin