I found this still sitting in unanswered posts. I couldn't believe no one ID'd it; it is so distinctive looking. So mainly I am bumping your post, to get some more eyes on it.
But I went looking. Does it grow kind of vining? The closest I found was solandra maxima, called chalice vine, Hawaiian lily, cup of gold vine, etc.
Here's a little more about it, with more pics:
I'm not totally sure that's it, but as I look at my picture right under yours, I think maybe so... anyone else?