Psychlone:
In order to get leaders on offense, you may need to take a different strategy regarding using elite units. I use elite units exclusively to make easy kills. This means that the majority of my elites are offense-capable units. Veteran units are the real backbone of an attack. Any attack that might fail, I use veterans for. Elite units should only be used when there is little danger of failure. In this way, I keep large "stables" of elite units and am able to make lots of elite-unit attacks, thereby having a lot of chances to get great leaders.
A side note: In my opinion, great leaders are very important in the earlier ages, but become downright unimportant once the modern ages start. Shield production levels become so great in modern times that even wonders of the world are quick affairs to build by conventional means.
I currently have a great leader that I have no use whatsoever for. Late-industrial ages, my society is mobilized (so I am limited to building military things,) I have two towns that can churn out a tank every single turn and my offense is sweeping forward too quickly for an army to be of much use... my great leader is standing around twiddling his thumbs.