*UPDATE: some sample screenshots (F.O.C.U.S. technology): link
To be honest, it doesn't look too different from what I've been seeing so far.
Saki season 1 Blu-ray BOX is scheduled to be released on 3/7 (2012). 48000yen.
amazon pre-order: link
*UPDATE: pre-order only.
*UPDATE2: more info via ultimatemegax
It is a 6 disc set covering all 25 episodes as well as all the DVD bonus footage. That includes textless OP/EDs, 7 picture dramas, and new BD-Box CMs. They mention that they are using a new "retook" master for part of the show as well. A new trailer for the spinoff is also included.
Extras include a newly drawn mahjong set (with a design unlike the prior three), a newly drawn box and jewel case(s), 3D card(s) that have all of the DVD artwork, a newly designed booklet containing character designs, background art, and more, and a lottery ticket to win a ticket to a joint Kiyosumi/Achiga event they'll be holding.
- An anime edition mahjong tile set
- A special booklet
- Newly drawn cover art.
*note: I believe saki was never aired in HD and rumored to be produced at SD as well. Most likely SD upscale.