They are very secretive in the wild and seldom come above ground. I've heard estimates that in the wild they spend 95-98% of their lives underground. It is also very dangerous in many of the countries where they occur, so not much study has been done. I've looked a lot and have found very little info on wild sulcatas. I think they might be one of the least studied species there are. They are extinct in at least two countries and my source speculates they are extinct in several more countries, but its too dangerous to go there and find out.
I have found no videos, and I think wild sulcata video would consists of a camera pointing at a hole in the ground...
The best source of info I have found is an out of print book called "The Crying Tortoise". Its by a French author and it has French text on one side of the page and English on the other. Well worth the money if you can find a copy for sale.