I contacted Bobross.com about acquiring an authentic Bob Ross painting. Here was their response:
Thank you for your interest in Bob Ross and the Joy of Painting.
Most Bob Ross paintings had many years ago been donated to PBS and educational television stations and numerous charities for fund-raising events, while others are currently in a private collection in the Bob Ross Art Workshop and Gallery in New Smyrna Beach, Florida.
While our company does not offer any original paintings or prints for sale, there are occasional Bob Ross paintings offered on e-bay, some of which, unfortunately, are of questionable authenticity.
We have so many other wonderful Bob Ross items available -- be sure to visit www.bobross.com to see all the paint kits, t-shirts and more.
Bob had put together a series of his favorite paintings which will be aired on public television as The Best of the Joy of Painting. Watch for this series to appear on the PBS educational channel in your area. If you take a few moments to call or write your local PBS stations requesting this series, through the magic of television, Bob will be with us for many years to come.
Once again, thank you for taking the time to write.
Bob Ross Co."