Kyle,
Being fairly OCD about this stuff, I'd also mention the following;
A few previously nine hole courses have gone to 18 since I played them but I haven't returned. They include;
Eagle Rock (16.3 Miles) - Original nine by Arnold Palmer Group, Second unplayed nine by someone from "Double Diamond Resorts"
Willow Brook GC - (16.7 Miles) - Original Nine by Calvin Miller, Second unplayed nine by Jim Blaukovitch
Sawmill GC - (27.4 Miles) - Original Nine by Dick Field, Second unplayed nine by Jim Blaukovitch
A few previously 18 hole courses became 27, but I hadn't returned.
Blue Ridge Trail GC (23.4 mi) - Original 18 by Brian Ault, New unplayed Nine by Dan Schlegel
Wedgewood GC (37 Mi) - Original 18 by William/David Gordon, unplayed nine by Jim Blaukovitch
Finally, Kyle's favorite Mountain Valley went from 18 to 36.
Mountain Valley GC (22.6 Mi.) - Original 18 by Herman Yaducufski based on routing by David Gordon who left the project before construction completed. Third nine by Dan Schlegel, Fourth nine routed by Dan Schlegel who I believe left the project and it was completed in house.
Also, I've never played the Donald Ross "Hill 9" at Silver Creek CC about 40 or so miles from home, which these days is played as a separate nine even though it was part of the original 18 hole course.
Perhaps more sadly, I still haven't played the "Executive nine" at White Birch GC (designer Ben Godshall) about 30 miles from home.