Sonic & All-Stars Racing Transformed

[NICKtendo DS]

Billy isn't in the game because he was planned and even went through the concept phase. However, they failed to come up with a proper design for all 3 vehicle modes, so he was dropped in favor of time and money.
Perhaps SEGA pitched him, but I think it's unlikely, because the purpose of the massive voting that was going on was to come with 3 characters (which became 7 due to the scale) we wanted Steve to pitch to SEGA. Billy did not make it into the list.