I was just thinking that it might be nice if some big structures, like churches and the like, would require some building materials which are objects, which means you wouldn't be able to put them in your inventory but had to carry them to the building site. This would mean you would need a lot of infrastructure to do large scale, late game, building projects. This would also mean that since you can no longer keep the materials in your inventory you can't port them through Boston but would require you to either transport them long ways from where they can be produced or produce them on site.
Examples of possible building materials that could use this system:
Stone blocks
Wooden Beams
That's actually all I could come up with..
I think this mechanic would be nice because it would building late game structures harder which would make the endgame more challenging, and make so that you can't just build endgame stuff far away from your old town and just port all the materials through Boston.