I was just searching "Lego Island Xtreme Stunts" in google images today, and I found this:
I've haven't seen these beta screenshots before, so I was really excited to see some new ones that look really different from the released game. Not only is the island layout different, but apparently there was going to be a multiplayer mode and an arcade mode!
I then decided to visit the site to see if I could find more screenshots. Unfortunately, there weren't any more. However, I found out that the site belonged to Martin Wood, who did art direction & management for Island Xtreme Stunts. He also did the character models and textures for Soccer Mania:
Here's a link to his site: http://project-orange.co.uk/