I must've gotten lucky. The last time I went down to L.A. I specifically asked the boss lady if I could visit Vivid and I got the green light. And guess what was there...
The owner knew it was a gig, and he told me that he already had a buyer but the person hadn't confirmed, so he offered to sell it to me. Their price was comparable to Live Aquaria DD and I was tempted to buy it, but I didn't want to risk driving it home.
They let me shoot a few photos so I couldn't leave without taking one of the DT:
Regarding mags and gigs, mags are EXTREMELY common, especially the brown or cream base ones. We have to remember that most are colonial, so when a collector spots a few, he'll most likely collect a lot at one time. Gigs are typically solitary. The mags with colored bases can cost more, though many times the exporter charges the same amount. It's up to the LFS if they want to jack up the price. I think it's fine for the LFS to ask for more money for a rare item.
I've found that mags are a lot easier to treat with antibiotics than gigs. In other words, if you find a mag, the changes of bringing it back from the brink of death is relatively high. They tend to respond right away, and it's an uphill swing.
Conversely, with gigs, even the experts are having trouble acclimating them. They have mixed results even with antibiotics. When I've treated gigs, I've been scared to look in the QT tank in the morning because I didn't know what I'd find.
So, to sum it up, I think gigantea -- the colored ones (green, blue, and purple) will always be more expensive than mags based on availability and ease of acclimation.