From what I've read he has a ranch in Alabama that is still in operation. The web site for the ranch is
http://www.agamainternational.com/. They specialize in Argentine Giant Tegu, Australian Waterdragon, Bearded dragons, Chinese Crocodile lizard, Morrocon Uromastyx, and Jewelled lacerta. His wife runs the ranch now.
If your going to get a tegu, leave this place be... Bert was top of the line but his passing left his wife and son incharge. his son wants the money, and neither of them know the care... alot of them are sick and dying.
Tegus can be puppy dogs if the right amount of patients and time is put in, I know this is an older post but if your interested i can throw together a care sheet for you if youd like