Well, as for P3 merchandise, I'll post the same merchandise that is shown on the D3 site. This is the type of "cristal figure" I was talking to you, Jessicat.
Thanatos Crystal
And another couple of interesting things:
Gekkoukan Bag
Inside the Gekkoukan Bag
T Shirts
Aegis & Mitsuru PVC Figurines
There's another PVC Figurine of Elizabeth and Minato, but I don't have the images with me, right now. Pretty common, merchandise I guess
I'll keep looking for something more "Obscure" and "Hidden"