Sega is continuing their 3D Classics line and they're bringin' some heavy hitters. They recently announced on their blog Sonic the Hedgehog 2 will be getting the 3D treatment, along with Streets of Rage 2 and Gunstar Heroes. Helluva lineup there.
These ports are likely still being worked on by M2, who have been doing a fantastic job with the series, bringing an accurate representation of the original games plus a plethora of bonus options. All while painstakingly bringing these 2D games into 3D bit by bit. They're pretty much the best in the biz when it comes to handling classic games and their passion really shows in their projects. Just read their interviews about the development of each game to see for yourself.
3D Sonic the Hedgehog 2 is set to release this September.