I am not a technician.
But please can someone explain, how it is possible that apple can get a 1136x640 in a small and thin device like an iPod touch or an iPhone 5 with bettter SOC and more memory and a very small battery? And gsm electronics(iPhone 5).
And this wouldn't t be possible in a device that is 3,5 x the size(roughly) than this new iPod touch or iPhone 5?
Why would this be impossible?
The battery could also be 3,5 x the size of an iPhone or iPod touch.
I think it is possible. It is just expensive and difficult to manufacture. But technically impossible?
No it isn't ......
The size of the screen is the very reason why it's so difficult. The backlight in the iPad mini is substantially more powerful than that in the iPhone 4S/5. That means a lot more heat and power consumption. If you look at the display backlight power draw at max brightness and battery capacity of some iDevices you can see why it will be difficult:
iPhone 4S: 0.42 Whr / 6 Whr battery
iPhone 5: ~0.75 Whr / 6 Whr battery
iPad 2: 2.7 Whr / 25 Whr battery
iPad mini: 2.3 Whr / 16 Whr battery
iPad 3: 7 Whr / 42.5 Whr battery
Adding a Retina display on an iPad mini would cause power consumption to shoot up to ~6 Whr, and heat output would become much greater as well. And that's with only a 16 Whr battery. To have similar battery life as it does now it would need a ~40 Whr battery, and at best you could cram a 25 Whr battery in there.
The only way Retina is going to happen on the mini, is if they find a way to reduce power consumption for the display by a substantial amount. Drop it down to ~3.5 Whr and put battery capacity at 25 Whr and that might be okay. Still be a bit heavier and hotter, but it'll be all right.