Don't ask me where I heard it but you might want to think "dual" as in offset mirage drives side by side rather than tandem. Boat won't get a lot longer.
Well, that is not too hard to imagine. Boat would be more like a catamaran having features like the Bravo with roller furling sail, but also have a pair of mirage drives. A drive & seat in each main hull, no amas, and a sail in the middle.
What would be disappopinting about such a boat is that it would have no kayak function. The Island (w/o amas) is a great kayak. The Oasis, with dual-in-line tandem drives, is also a great 2 person kayak. I bet car-topping such a boat would be next to impossible.
I sail my Island alongside both a Hobie Wave and a Bravo - have friends with each and we plan sails together - neither one points as well upwind as the Island. With daggar board I can keep a steady upwind course while Bravo & Wave are having to zig-zag.
I hope Hobie's new boat offers more speed than the Island, 2 people, and keeps its e-z to sail and super upwind sailability.