In my quest for mounted command, I picked up the Roman General pack from Crusader Miniatures. It comes with one mounted and one dismounted general. They are from their Punic Wars range, a bit earlier than the Marian/Caesarian era army I'm doing, but I think they look fine.
Nice, clean figures. Here they are compared to a Wargames Factory legion (which will make up the bulk of my infantry) and their metal Caesar figure on foot.