In Chicago during and after the depression until after WWII, Robert Bruce Harris owned several courses, which contributed to his design style of round bunkers placed exactly one gang mower away from the green, large greens to spread wear, etc. Most gca's take a little different look at their designs if they are the ones paying for maintenance.
The Jones Family owned Coral Ridge.
The Matthews of Michigan owned a few.
In fact, I bet its not uncommon for gca's (and contractors) to at least be partners in at least one course they designed. I know I was (at least for a while, but I got out) It got pretty typical in the boom of the 90's. In general, I felt better about diversifying out of the golf industry, figuring what happened would happen at some point......