Default [Q] Creating a flashable zip from a factory image


I have been using custom roms and with the advent of xposed, I am now able (as a lot of people) to use stock android + modules.

But I am disliking Kitkat on my Nexus 4. I would love to able to have both roms (4.4 and 4.3) using multirom.

The stock rooted 4.3 zips through the internet are not available anymore. So I started trying to create my own, using the factory images.

Browsing the net, there´s no real tutorial for doing so - only how to flash an update by adb or sideload, or how to create a rom from another custom one. I could install the factory image using toolkit in my Nexus 4 and them copying the system folder but I would like to do it in the pc.

So, sorry for the noob question here but... is there a way to do it? Maybe knowing how I would be able to do this with all the factory images and even hosting them...