If you want to build a consistent brand, sometimes the best way is laying the foundation by transforming company/team culture, and preaching-by-example while trying things first internally.
With the help of our creative director Todd Matthews and all our internal customers' input, we were able to prove that a scalable, modular, and consistent visual language was still able to express the multiple intended messages of internal teams and initiatives. Later on, we moved these successful process & architecture to public events.
Our Creative Director Todd Matthews (with the help of other handy internal designers like Smith Suth, etc) was always able to elevate our "internal brand" all the way into "internal culture", via the extrapolation of baseline guidelines into beautiful pieces of highly celebrated office art, and coveted swag (t-shirts, stickers, banners, etc).