PS: it is possible to flash most android phone with a real linux system 
tough normal users wont do that.
tough normal users wont do that.What? Seriously? Link, pretty please?
It differs from phone to phone. See http://forum.xda-developers.com/index.php
Hopfully it would give you an start.
Anyway if you got root, why not download one of those Linux installers? It works like an image file you boot up, and can communicate with it over a VNC client. It was how I did it with my Nexus some months ago, but hopefully it's better solutions out there now
Take a search