From the pictures I've seen of his enclosure, I don't think a fake rock wall would work in his enclosure.
Personally, I reckon it would look pretty good, providing it wasn't a deep one. If it was only a shallow reservoir, I reckon it would be ok. Not that I know much about lizards, but that's my opinion, for what it's worth. Depending on how it is set up, it might give them extra climbing space as well. Just MHO.