I still maintain that the marquis can be a blank canvas, there are no side boxes as such, they can simply create some faux box panels as what we see in the photo is part of the Colonial and not the set. They can also go overboard with the drapery in the roof, paint those ugly boards black (or remove some, last time I was there, Evita, some looked like they were ready for fall out) Plus they have a decent size lobby to decorate.
http://www.flickr.com/photos/27199361@N08/ Phantom at the Royal Empire Theatre