Forgive me for being skeptical that Intel would place restrictions on computer makers that would require them to redesign most of their machines, and that Apple would be willing to do it.
The MP is three vertical boards with an air channel in between. It would be insane to try and design a mini the same but shorter. There's just no reason to make the mini that complicated when they can put everything on one flat board, same as they have always done. Especially when two of the three MP boards are for GPU, and for the mini they'll likely stick with using the GPU built into the CPU.
First, Intel plan to focus mostly on Ultrabook, NUC and All-In-One segment.
The segment where you don't need another GPU, apart from the one built into the CPU. And where you buy whole computer, not different parts.
Second thing. Going with Xeon for Mini soon will be ONLY possibility for Apple to offer any other computer with GPUs. Mini in current design is dead. Why?
It can only fit 45W of power envelope. And the idea of using it as an AppleTV, but just better is not good idea for Apple.
4.5W TDP Broadwell processors are made specifically for that segment. For computers that will run fanless in the living room, and help increase the impact of Television on users.
Apple has its own way, and idea of that. iBeacon, that will recognize you just by the smartphone you are using. iBeacon, that will help controlling the house with HomeKit. iBeacon that will be a console for games from AppStore. That will stream, music, TV shows, moovies and youtube films. Or will run everything from built in hard drive. Those 4.5W CPUs are an answer for Apple A8.
Mini in current form HAS TO DIE in order to make room for that kind of hardware for living room.
Mini Mac Pro with quad core Xeon E3 and dual GPUs will be far better computer than current one. In every single way, and everywhere, where it was meant to.
Basic desktop computer in Apple mind right now is the basic iMac.
That is what i believe Apple will do in few months.