The biggest issue you'll face rob would be adhesion. A chrome surface can be tricky to prep to accept paint. I remember when i repaired and repainted the chrome grille surround, it took some serious prep work to key the chromed surface.Maybe worth looking into wet paint with an airbrush, much more controlled application so less masking up, I'm open to any option to be honest as long as it lasts more than a couple of years.
If you were wanting the do the roof bars too and if you actually fit cross bars from time to time, powdercoating is a good hard wearing option. My cross vars haven't marked my rails at all but then again the glossy finish isn't as good as i would like. Seems to be swings and round abouts.
As i said, hopefully in the new year I'll be starting the cosmetic work on my bus, and a proper de chrome is on the list so I'll let you know how i get on.
Alex