Tried a full size one, couldn't stand the weight. Monster great screen needs a monster great battery (4490 mah vs 11000+).
That's not to say that I'm not excited for a retina mini, there are just significant challenges.
If the DPI/PPI of the 3/4 were sliced out for a smaller screen (making a proportionally smaller screen), the unique resolution would cause software chaos with developers. Unless iOS 7 or 8 (and all apps) can be made resolution independent.
Otherwise, the exact resolution of the 3/4 screen would have to be squeezed into a smaller package 1) creating an even higher dpi, 2) even higher screen production challenges (though apple loves those), 3) necessitating the same video card and perhaps even stronger backlighting in a smaller package, 4) with silly power requirements.
So maybe mini 3, with mini 2 sold along side at a lower price, after software or tech makes it less difficult. Meanwhile, the mini 1 is an 'awesome piece of kit' with more functionality+portability then I've ever seen.