'Virtual Realities' by Claire Carmichael (Score 1)

... had the same idea. The novel is around 8-10 years old (?), and aimed at a fairly young reading level (12-14 year olds). In the book, the ball rolled on a sort of ball bearing treadmill, and individual balls could be moved up and down to simulate floor textures. (this is about as far as the book is worth reading, because after that dinosaurs start being created by some little turd's mind.)