The only thing I can tell you is that in the six years I managed Robert Schoeller, he never did a single bridal portrait. Neither had he in all the years prior to my working with him. Honestly, I don't think it's a big demand item, but some do them.
I have a Bridal Gallery on Stroke of Genius, so there were enough to warrant that. However, two of the portraits are actually members of a wedding party rather than brides. Take a look:
http://www.portraitartist.com/bridal.htm