Ah! It's great to see other OZ fans here. (Thanks for that list Fozzie, good to see you have extensive knowledge of the OZ universe!) As a huge fan of the books, I'm in love with Return to OZ. I thought it captured the look and feel that the books portrayed. It basically combined the elements from 'Land of OZ' and 'Ozma of OZ'. The score by David Shire was perfect. (It's out of print and goes for bookoos on ebay but you can download the entire score at returntoozthemovie.com if anyone wants it.)
I would really love to see this series be made from scratch and start all over with the original story. Just as long as it takes the approach that Return to OZ did. Actually, I'd love to see it take off from where Return to OZ left off, but that film is not recognized by many, sadly. I wonder if todays audience would be more excepting of a non-musical version. It's sad to think they might not. But you never know. Most people associate OZ with the colorful musical. And I will say the MGM musical is a classic landmark film that will remain an unprecedented masterpiece. But in all honesty the overall tone of the film wasn't like the books. The books, while delightful and very funny at times had a dark side to them as well. And it wasn't just the wicked witch scenes that were dark(her role in the book didn't seem as prominent in the book as it was in the musical). I would love to see the scene where the tin man lops a wolf's head off.
Sadly, the Thompson books are out of print... I think you can get them off of abebooks.com though... I haven't read them, but I'm dying to read Jack Pumpkinhead of OZ.