Ron, I got 2 T. gigas from Clamsdirect. For a while he has some left but finally they were all sold. Before I got my T. gigas, I was looking and looking. If you wait long enough, there will be another shipment. Maybe the supplier is holding out - until the demand is there before they ship the clams to US.
I got a 6" and a 4". 6" is doing well, as pictured. But 4" is surviving - but no visible growth - and it is not as colorful (fewer blue spots) compared to the larger one.