So I figured out how to manipulate Minecraft.jar files to get rid of annoying villager gonzo noses and give them hair, but they only show up as changed if I alter the minecraft/versions/1.7.4.jar.
I successfully changed every villager and was flying around in creative mode, admiring my work. I restarted the game and all the files reverted. Now every time I launch the game, the altered files revert every time to the gonzo. I change the file, open the new file to confirm it is changed, and launch game. Gonzo. I recheck the files and they are back to original again. Very frustrating!