I really like the concept. We would like to add the concept in the game.
The idea about bonuses is very good. It helps up give some new dimensions to the game.
The implementation details are lacking a bit but this is no problem for us, we can easily tailor it to an acceptable solution.
Here is a perquisite before this can be implemented:
-Governor Preference of port
This has been discussed before, it is basically a way for players to declare their interest on a specific port. The one with higher influence chooses 1st. Current model will be maintained for those that state no preference.
However, I am not sure if an inn should be a governor building. But it makes sense as you would want only one active inn at each port.
To make greater use of such building, we need to work towards the IC extension of the game in version 2.0 (We are at 1.8 so long,because we want 2.0 to be something that adds a whole new dimension to the game). Before this, we got ship specialization.
So I think we have a heading thanks to this post.