Welcome to the forum Copper2, I'm sure someone here will be able to help you out or know where to go to buy them. It would help if we know where you live or part of the country you live in.
i wish, we tried growing a few on the west face of the front ditch and they limped along for years but never got very big and eventually Mom covered them up. the cedars and pine trees are getting big enough to have overgrown them by now. so if you plant them on a slope of heavy clay and facing west give them a better chance by making a small well for them to hold some of the water as it goes by. once they get established they'll probably not need any care at all other than weeding around the edges...
Good luck in your yucca search. They are popular landscaping plants.
I had the wild ones all over my property in San Diego and I have to say they are my least liked plant. Not fond of anything with thorns really, but the ones that can go through a boot and leave a sore for days are way down there in my popularity poll.
I think the cultivated varieties are less brutal though.