Nope. We'd have to remove a faction for that.
Now that I like. Can't do the German idea though. For starters there is no reason for us to assume that Germans will randomly migrate around 100BC in this game. Secondly, the Germans merely hastened the event - it was probably going to happen anyway. The latifundia idea is sound though.
It will happen late in the game

We could trigger some rebels with the latifundia penalties, thus the potential for the social war

It gives the player some control over how
their republic is run

It should be relatively easy to pull off I'd imagine
