You forgot Kautilya, probably my favourite Realist-style writer, although that's not exactly rare - noone teaches him these days. He was a champ and a devious bugger. He was running India through his puppet king around the time of Alexander the Great. If you can get a hold of a translation of his Arthasastra I greatly recommend it. He's one of the few political pragmatists whose manuals of rule have survived the ages.
He's particularly interesting when you compare his work to The Prince. The advice is extremely similar, certainly enough to suggest that either Machiavelli's a rip-off, or that there really are some universal truths in politics that survive the ages.