Sega is apparently planning to release an HD remastered version of the Dreamcast game Sonic Adventure 2, assuming that a now-removed product listing at Xbox.com is accurate. The originais no longer there, but the Internet acted quickly to preserve its juicy information and screenshots on NeoGAF.
Assuming the product page is accurate, the XBLA release of Sonic Adventure 2 will be happening on October 3, 2012. The description refers to the game being an HD remaster and listed features include offline multiplayer, leaderboards, and content downloads. We're checking with Sega for confirmation, but I think it's safe to assume for now that an HD version of Sonic Adventure 2 is definitely a thing that is happening.