http://io9.com/10-things-you-probably-didnt-know-about-star-wars-ret-1383276948

A set of fun facts gleaned from an advance copy of Rinzler's Making of ROTJ.

Including this tidbit:

...a running theme in the book is that everybody except Lucas hated the Ewoks, those invincible teddy bears. They were a sticking point at every stage of production, and concept artist Ralph McQuarrie refused to work on designs for them once he realized what Lucas actually wanted.

I didn't think it was possible for me to love Ralph McQuarrie and his work any more than I already did, but apparently I was wrong.