Conrail, Penn Central (orange/white logo), Pennsylvania, New York Central (cigar band), Jersey Central (Red Baron), Lehigh Valley (snowbird), Reading, New Haven (C425/U25B scheme), Chessie System, B&O, C&O, Western Maryland (black fireball), Georgia RR (blue and silver, Western Ry of Alabama, Atlanta & West Point, Clinchfield, L&N, Atlantic Coast Line (purple), Seaboard Air Line (citrus), Seaboard Coast Line (black), Seaboard System.
The way CSX management would most likely choose to do Heritage diesel units is to apply the names of the predecessor Railroads on the standard CSX locomotive scheme.
Andrew