STM makes one.
http://www.azionemoto.com/mall/product.asp?pid=52 My opinion is that the few cases of damaged spines on the DP product resulted from the incorrect installation of the flywheel retaining nut. They’re very difficult to install properly, so I recommend using the Nichols replacement nut. It’s my understanding that the DP unit has a two year guarantee if installed by Ducati - but of course if it fails, there’s now metal shavings inside the engine that can cause other damage.
Here’s a case however where one 1,000gm flywheel doesn’t equal (in effect) another 1,000gm flywheel. The reduction in rotational inertia is dependent upon WHERE the weight is removed. Because the rotary inertia is proportional to the square of the distance from the hub, 100gms removed from the outside diameter has more effect than the same amount removed across the face of the flywheel.
You can have your stock flywheel machined, but without doing a stress analysis it’s hard for the machinist to know what shape gives you the minimum rotational inertia with adequate strength everywhere. That’s why a lighter material in the same shape makes some sense. Further the inner steel splines on the STM unit place the heavier steel near the hub where it has the least increase in rotary inertia.