Due to the size (and therefore battery/power constraints) will the rumored iPad Mini have a 4G model? If not, will it have 3G or just no mobile connectivity at all.

I imagine it will have 3G connectivity but not 4G. In addition to the screen size and non-Retina display, the lack of 4G will make this product more affordable and thinner.

Is the price difference between a 3G radio and a 4G radio that significant?

Also, what pricepoint do you think Apple will be brining it in at?

I see $199/$249 and I don't think Apple cares what the price difference is between the two radios but my understanding is that a 4G radio is currently larger in size thus it would be harder to squeeze it in and keep this device remarkably thin.

But at the same time, if the rumors are true, they are putting a 4G radio into the next iPhone (which is supposedly thinner than the 4S).

Depends on how large they want the battery in the iPad Mini.

Yes, 4G is in, NFC is not and I could've probably told you that the moment I saw PassBook requiring barcodes (who cares though, NFC is dead in water it would seem). The next iPhone is supposed to be thinner and it makes sense, after all they did increase the size of the overall device so more area to work with.