I'm trying to think seriously about if they did retina on the next mini, what resolution they would use. Obviously they wouldn't double 1024x768 equaling the full size iPad, as that DPI would be crrraaazy (awesome) and outspec the larger model. I'm wondering what mathematical multiplier would make it easiest for them to bump it high enough to jump over the 300dpi point, yet not make it where they have to do subpixel rendering or other calculations that could blur it some. The extra resolution would also impact battery, demanding a larger battery. This may be the simple single block that would make Apple not put a retina in it until power consumption of high dpi screens becomes the same as current lower dpi options.