For your idea Warlord, the best way is Firescythes idea.
In effect, we would have to fake there being multiple clients from the server. This is different from Kirby_422's ai-player fusion in that we would have to code our own ai, pathfinding and all.
Would be a start, however. It is probably the most feasible idea as well.
Another thing is if done right, this would work great for machinima peeps. (I'm looking at you Silicon)
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