One of the products that I currently use now, that I didn't use in theatre very often is laminate. There are literally hundreds or even thousands of textures, colors, and patterns available in laminate & it is just as easy to put on laminate as it is to do a good paint finish. Obviously the important difference is that you need to be careful with your seams as they can't be hidden.
I also use laminate for covering up the grain on wacky wood - using a cheaper matte laminate provides a nice paint surface that is free of blemishes. It is also good for when you need to get rid of edge grain. While it isn't every job that requires such attention, it is a good option when applicable.
For laminate options my fall back choices are usually the most common; Wilson Art, Formica and Chemetal.
However, I just got in samples from Inter Source and they have some nice options & a very complete collection of wood grain options. Also, they offer 2x8 sections of stamped ceilings - something I have used several times over the years in theatre. Also, this company sells Valchromat a through-colored MDF.