> There is no NES game based on "Mother" unless you count what has been called "Earthbound Proto" or "Earthbound Zero".
Perhaps you should do a bit of reading... (http://www.lostlevels.org/200407/200407-earthbound.shtml)
Short answer: The 'Earthbound' NES prototype ROM is real. It is also far more than a simple translation, as it also changes numerous gameplay aspects. 'Earthbound Zero' is a hack (of said prototype) by Neo Demiforce that allowed the the game to be playable in Nesticle. Today's emulators can play the original dump without any problems.
Recap: The 'Earthbound' NES proto does not use mid-scanline CHR switching. The game 'Mother' does use mid-scanline CHR switching while the menus are open (in order to display ASCII text and hiragana/katakana at the same time), as seen below:
P.S. If you don't get this note, let me know and I'll write you another.