I'm using the Unified Refried theme with the 3D box and "cart" view. I have switched between the other Unified themes, and none of the "default carts" would appear, even after using "refresh all images" in general options of BigBox. I had installed "Default Assets" so I'm pretty sure those "defaults" should come up, including the "default box-front" from the default assets package, which doesn't, and instead shows the actual box-front for the actual game.