I have read with considerable interest the postings on the subject of CSX Heritage Units and would like to weigh in with my thoughts.
I find the thought of CSX honoring their heritage by painting up a group of locomotives in predecessor schemes to be a great idea. Yes, it has already been done by others, but the PR upside seems to be well-worth the efforts. I am also an egalitarian, and think that more units are better than less. With that in mind, here is my list of railroads to be honored with CSX heritage units.
ACL, SAL, SBD, Family Lines System (yes, SBD and Family Lines system are close in appearance, but so what?), B & O, C & O, PM (using the Pere Marquette Streamliner passenger scheme from 1947. It was great on E7s and would look good on modern power too), Chessie System, WM (I can't decide between the classic black "fireball" scheme and the red, white & black scheme, so do both), L & N, Clinchfield, NYC, PRR, Penn Central (come on, you can't leave it out), Conrail (using the beautiful "White Face" Quality scheme from the SD-70ACs, and SD-80ACs), LV, RF & P, New Haven, NC & SL, Georgia, Atlanta & West Point, WRA, and of course CSX (with one unit painted up in each of the principal schemes used, i.e. "Stealth", blue & gray, "hockey stick", and "dark future".
To take things one step further, how about a train of freight cars, each painted in original predecessor schemes, with one car painted for each of the above named roads plus a CSX caboose. Let it tour the entire CSX system.
Tie it all together with the expanded motto "Celebrating Our Yesterdays to Enhance HOW TOMORROW MOVES". Tie it all in to B & O's 185 Anniversary if possible.