I have been looking as well. The only solid lead (solid meaning consistent) is Bob at iBlueWater. He quarantines his gigantea for a minimum of 4 weeks. Everyone I've spoken to are very happy with their purchases from him. The only catch is that his prices are high (3x what I spent on my other gigantea) but it also makes sense since his specimens are healthy and being compensated for his extra effort is fine by me. I just can't afford it right now.
In terms of importing and the LFS getting them, despite what some people have told me, they seem to be seasonal -- maybe not in the sense of particular times of the year but more that they seem to appear in batches. Two LFS had them about a month apart. Then none for months, and I'm still waiting.
I've spoken to a few wholesalers and all say that they get them from time to time but it's not consistent. Since the survival rate of gigantea is terrible compared to haddoni, my understanding is that most would rather just import haddoni.
Hopefully you'll find a good source and can pass along the information to the rest of us. I'll be sure to do the same. Good luck!