I'd be interested in a robe like that as well, just for times when I take Gatanas about the town at night, and I want those excellent glowing tattoos of hers to be seen through the clothing. I know there are some shirts you can by in the Pelagiad via COV I think that are transparent, in black, white, and red. I guess the trick would be can it be done for a full robe?
Unfortunately no - like Westly said, robes fully remove the chest, upper arm, groin, and thighs of any character that wears them, regardless of what actual body part you slot the robe into. Shirts can be made transparent for Better Bodies if they are slotted to the left ankle body part, but because robes are worn over top of armor, they have to remove the parts they remove in order to not clip hideously with cuirasses, pauldrons, and greaves - this is hardcoded into the game. Skirts are the same way, removing the groin and thighs; any transparent Better Bodies skirts are classed by the game as pants in order to get around this.
True robes (i.e., that equip as robes and not shirts) that show skin require racial scripting if they are to be released or given to companions. Westly's described method would work and be rather nice looking, and could even be done fairly simply to any Better Bodies skin-revealing "robe" that has already been made. You'd need to edit the mesh and the .esp for said robe, but the end result would give the effect you want and the edits are simple.