On the 3rd of April, a list of Announced, unannounced, and cancelled games that are possibly coming top XBLA on NeoGAF gaming forum. On the list of games was the Famous game Sonic Adventure 2 along with Sonic 4 Ep II and many other SEGA titles. Originally posted by a forum member with no source as to where the list came from it is possible that this list is partiality fake. We will keep you updated on the matter.
Original Source here: http://www.sonicretro.org/2012/04/rumor-sonic-adventure-2-coming-to-xbla/