Hmm... It's interesting, but I'm not so sure this is such a great idea. Seems like we'd be hiring a sub-GM or something. Few GM commands... Even just giving the marriage command to a regular player could be dangerous. It could easily be abused if given to the wrong person. Discounts and such doesn't seem so fair either. Even we GM's don't get discounts on items (not that we need them, but still). Giving a player the recall command (or as you call it: the ability to move someone 3 cells away), is a huge risk. That could also, be abused even more so than the marriage command if given to the wrong person. I can see problems and complaints flying left and right from that one. With all that said, I don't see too much of a point of administering a President. Why not just hire them as a GM when the time comes around, if they are good.
I'm sorry, it's an interesting thought, but I don't think it's a very good idea to implement.