I'm pretty sure Z-Stacks on a diabolo would be pretty much impossible to grab, unless you have hands like Sagat's. Do you have hands like Sagat's?Nick.
Diabolo88 are you maybe thinking about somthing like this http://www.yoyonation.com/product.php?productid=16480&cat=332&page=1? If so i think LZ is working on making some.
I *think* Nevs done the Fly mod