Hi, Chris. One suggestion would be chair rail cap moulding installed up-side down. Another would be aluminum angle extrusions. Check the dimensions since there are 2 thicknesses of drywall available (5/8" and 3/4") and the aluminum angle goes by outside dimension, not inside. Nail the chair rail to the studs or drill and screw the angle to the studs.
My wife does not permit me to make color choices. Maybe that's why all our walls are "eggshell".