As others have noted, this kind of game requires a poor opponent. A good map helps, too, so this is all fairly meaningless. But just after reading this, I had this game:
http://warlight.net/MultiPlayer.aspx?GameID=1622535
At the end of 10 turns, I had conquered all of Eurasia plus Indonesia, for an income of 52 armies.
So there you go. At the least, low 50s is possible.