Bukkit

First off, no. Not players. I'm with you 100% on not being able to control other players.
The Citizens plugin has something like what I'm suggesting, where you can spawn entities that have the same model as players, but they are npcs and are somewhat controllable. It would be really cool if your plugin could spawn and control human npc entities. Bukkit doesn't have an out of box way of spawning human entities, so you'd have to handle that.