After looking at an old post from cactusfreak, it looks like there maybe some different forms. If you're out there cactus freak I'd really like to know how your C.giganteas from 3 different sources looks now. I can't decide what source to order from, but will probally try to find a proven hardy one.

How many different giganteas are there?.

Nature Products has one, and if I remember right it has purplish stems. They sell seed, but I hear it is hard to germinate.

Here is a link that might be useful: NP