Since I haven't seen this information or these scans floating about the internet, I thought I'd go ahead and share them all with you. Below are a handful of links to .pdf files you can view on the web that have scans from the upcoming Legend of Zelda 25th anniversary book, Hyrule Historia. (Psst, there's Midna art!)
So, as follows: [link]
(Conceptual artwork of Skyward Sword Link, his Loftwing, and Zelda) [link]
(Appears to be pages regarding character and game information) [link]
(Conceptual artwork of Twilight Princess Link, Wolf Link, and Midna) [link]
(A game timeline showing the forms of both Link and Zelda through the years)
You guys won't believe the conceptual ideas behind Midna. I have to say I'm especially fond of her "true form" that wasn't used. Enjoy!