The current XBLA offerings from Sega include, for the most part, games from the Sega Genesis era. Things like Sonic the Hedgehog 2, Ecco the Dolphin and Golden Axe. Thankfully, that's changing.
While the publisher is also bringing games like Virtual On Oratorio Tangram from arcades to home, it's also digging in a little deeper, apparently. The Entertainment Software Ratings Board has new ratings and descriptions for Shinobi and Altered Beast, which appear to be the System 16 arcade hardware versions.