I can't believe I"m going to let myself get sucked into the ongoing magsafe debate, but here goes...
One simple little fact tells me that the mini will not use magsafe. Look at the picture here:http://www.apple.com/displays/features.html
The connector is L shaped. How exactly would that work? Apple isn't going to put the port on the side of the mini, so it will be on the back. But in what orientation? They could put it along an edge, but then the cord is going to stick out from behind the mini, which would look ridiculous. So Apple won't do that. If they put it in the middle or oriented so the cable doesn't stick out like a rooster tail, it's going to block other ports on the back of the mini.
Also, from this photo
, it really doesn't look like the cable is long enough. Your laptop is going to be someplace close at hand because you will be coming and going with it. But a mini could be tucked away in a corner not near your display, but that cable length doesn't really allow that. So the current
cable that ships with the Cinema Display really doesn't work for the mini.
The cost-saving argument doesn't really work either. The current connector used by the mini is likely cheaper to produce than a magsafe connector. As for the other end where the transformer is, unless Apple makes drastic power-saving design changes, neither of the existing MB/MBP adaptors are high enough wattage, so Apple is going to have to design a new transformer anyway. They can't simply reuse the current MBP adaptor. A final note on cost savings, the laptop adaptors are designed to be small and portable. My guess is that because of that they are more expensive than a plain old brick style adaptor that can be hidden behind your desk where size doesn't matter.
The ease with which a magsafe connector can become disconnected is also a strike against it for desktop use. There have been times that I've picked up my MBP not realizing it was plugged in. I didn't even feel the magsafe come loose until I heard it hit the floor (the end of the connector, that is). The notion that Apple would "rig a clip" is just silly and un-Apple-like.
So it seems like the only reason folks are arguing that it will be a magasafe on the mini is so they can us it with the new LED Cinema display. There's just no other logical reason do use it on the mini. So to those folks, I'll offer a solution. Obviously Apple wouldn't sell a display with a three-headed connector (mDP, USB, power) that is only useful with laptops. What are we supposed to do, leave the power connector dangling unused? Also very un-Apple-like. So if you look at this photo
, it appears that the connector is not hardwired into the Cinema display.
So I suspect Apple will do one of two things. First, it could sell a cable that only has mDP and USB, no power. This would allow you to use the new display with a desktop Mac without an unused power connector dangling around. You could even even use it as a 2nd monitor for an iMac, for which there is no way the Cinema Display puts out enough power to run an iMac (or a Mac Pro, for that matter). In this case you would use the power adaptor that came with your mini to power it. The 2nd option is that Apple sells a cable that includes power for the mini, but with different connector on the mini end.
Either way, since it would be silly to use magsafe on the mini for the reason stated above, and since Apple will need to sell you a new cable to use the Cinema Display with anything other than a MB/BMP anyway, they are free to use a simple, more secure design for the plug itself. There will be no advantages (and a few disadvantages) to using magsafe.
Now can with end this never-ending debate of whether it will use magsafe and get back to the far more important issue of Firewire?