Over a year ago, I visited a DBZ website that had little tidbits of Dragoball-related trivia. One of the things mentioned was that if you look closely at the background in the World Tournament stages, Luffy appears in the audience.
After checking it out for myself, I spotted a character that resembles Luffy, except the vest was blue and so was the ribbon around his strawhat. I've played both, the Budokai series and the Tenkaichi/Sparking! series and I gotta say TWO things…
ONE: I spotted the character in both series.
TWO: Bandai recycled the World Tournament background characters for both series.
I wish I could come up with a screenshot for you guys, so I gotta search online for more details regarding this......