I know the thing you mean although I can't help you find one and I've never seen them used for fuchsias. However, I assume you know that you can grow standard fuchsias perfectly well without any framework other than a stake?

Here is a link that might be useful: Growing a standard fuchsia.

If you can't find one, you can make one pretty easily. Just invert a standard wire 'bowl' used for hanging baskets over the top of a wooden stake you will be using to train your fuchsia tree. Anchor as desired. Make sure to remove any of the hanger appliances :-))