Oh not that, my question was if there will be some way to create that "3Dness" from a single texture. Not repeat the same texture X times, because as you said, then will be 2 axis just extruded.
One of the simple ideas was move/span in wrap mode the texture, one pixel left&down, in each slice/tile, to avoid that extrusion, still the result not will be as nice as a real volume texture but may works enough.
Other method will be more complex, like keep the center of the texture 254x254 , and the borders used for the other axis, change in each slice to recreate that 256x256 texture in the other sides/axis. 0 extrusion, each face will have that texture.
No idea how this ideas may work, at the end, is some method that from a single seamless texture, the tool can do the process and give you a volume texture, with no extrusion, so you can map any object seamless in any face.