The twin disc I always knew could be made is featured on MotoIQ:
Project EVO VIII part 4, Getting More Trackside Grip, Killing Some Slip
When I say a twin disc should be able to hold more torque than a single disc
and have an easy, smooth, stock-like engagement I'm talking apples to apples and Mike explains it in that article. It just happens that most twin disc clutch setups are not made like OEM clutches and are aimed at race cars so they don't have any of the smooth engagement tech that OEM clutches do. That is, until Cusco/Exedy stepped up to the plate.