I haven't seen any moves to make the gear diff available for the mid car unfortunately. Thats not to say that there isn't anything going on behind the scenes though
It would probably be quite a lot of work to get it to fit as they would have to redesign the gearboxes, t-piece etc, just like they did the rear motored cars, but also they might end up having to redesign the rear bulkhead, and probably the layshaft would have to be slightly longer compensate for the extra width of the gearbox.
I can imagine it would be quite a lot of work if they did decide to develop it.
Anyways here is hoping that they do but I wouldn't be surprised if they don't.