Puzzle for Apple:
Broadwell is almost ready. I think if Apple wants, it can get access to the first batches of Broadwell. With the mini being the first to update, Apple could choose to go Broadwell. Apple skipped architectures before on the Mini (Core2Duo straight to Sandy bridge).
If it maintains the current form factor, and moves to Broadwell, we will have a machine that both outperforms the top of the line iMac, and the entry Mac Pro. Maybe its Iris Pro 2nd gen will be no match for the GPU's in the top iMac/MPro, it will still be very decent, and fast enough for most people. Apple will kind of kill its own market.
So Apple almost HAS to shrink the mini. It is completely useless, I have no idea how they are going to market it. The current one does 11 watt idle, maybe they say this one is 5 watt idle or so, and even half the amount of materials used. Not very much sense on what is already one of the most efficient computers, but hey, they can sell it I guess.
And by shrinking they can increase profit. They can tie-sell extra RAM/SSD etc. The problem is they might kill the Mini with it. One option is they really drop the price, so people can start using Mac for say 400$
I really don't know why people want PCI SSD on the Mini. It has 2 SATA 600 bays, and as we have seen, using those 2 bays for generic cheaper-than-apple-pci SSD's in RAID-0 already makes the Mini outperform the new Mac Pro on disc tasks.
But we never know. With the last Mini update, I had the idea it was from a separate company within Apple doing its own thing, not taking care of how it would compete against iMac, Pro and Macbooks. If the Mini team comes with a Trojan horse again.....
----------
I guess this would not work with the 1 chip setup of the Mini.
The current form factor can have 2 chips. See the 2011 Radeon Mini.