From Sega World Weekly:
Thought some of the folks here might be interestedSTOP PRESS - Sometime during the day a video of an
un-released Dreamcast title will go online at
http://www.gaming-age.com/ That title, is Streets of Rage.
Quite why the game was never released remains a mystery at
the time of writing, but never the less this will certainly
be a video worth checking out.