Finally, after all this time, I found a pic of the Deidara-copy:
She's called "Charmcaster". Now that I see her again, the appearance really isn't all that remarkably similar. But the fact that she fights with "magically-controlled exploding clay dolls" and the pouch with the mouth-like zipper just
screeeeams "Deidara". Oh, and her cloak does have a very similar look to the Akatsuki cloak, style-wise.