I know what you are asking about (Hurricane Systems?) but I also think they have stopped production. Given that I hunt almost 100% private land, alternatively I usually buy the 15' metal top ladder stands at Sportsman Guide and merely hang a stand off to one side of them. It serves the same function and gets me about 16' or 17' feet.
I started this when my children were very young for a safe ascent method into the tree and just never stopped doing it. Now that I'm "old" I find it very reassuring to have an easy way to get into a portable. I always use a HSS safety line and the whole thing can be taken down and moved to another location is about an hour.
I have actually used the system on public land as well but it isn't as practical in most cases.