It seems Bethesda releases a limited edition for OB with contents from the GoTY and the CE editions and a $10 coupon for Skyrim.
http://www.nitrobeard.com/home/tag/the-elder-scrolls

I don't know whether or not it's confirmed, or if it is available outside the US.

http://www.gamesas.com/index.php?/topic/1194069-oblivion-5th-anniversary-edition/