Funny you should mention the Tom Sawyer anime. I was flipping channels at my friend's house the other day and it was actually on some channel I've never heard of, like many of Dish Network's channels.
It probably is the Tom Sawyer anime you're thinking of though, since, as far as I can tell, this has ironically never been dubbed into English.
oh and the look on her human face as she's dreaming of this just makes me think they're going to place her in the same nuthouse as Dorothy in Return to Oz. ENOUGH OF YOUR CRAZY IMAGINATION