There is not.
I don't think there needs to be.
The only existing rule technically is that when selecting your leaders you do so in reverse order.
Assuming the leaders are close to balanced this shouldn't matter, but at least in the case of the guy that gets the merchant ship good for free, it works well with going first.
I don't think it is a big issue. If you want to go first you can spend an action to do so, and quite often that action is taken.
If you want to change your stature take it yourself.
Selecting the leaders in reverse order IS the mechanism for balancing out starting turn order.