ToeJam and Earl 3: Mission to Earth came out on Xbox, and, um, it wasn't very good. Now it turns out that Sega had previously made a different version for Dreamcast that never quite came to fruition. There's a now a video of beta gameplay, and plans in place to hold a fundraiser so that the code can be released online.
Obviously the footage doesn't look too great, as the game was very much work in progress. Would you be interested in seeing more of this?