We visited the Porsche showroom in Auckland. This one isn't rainbow, but is reflecting the very colourful car that was parked right next to it. I was thinking that maybe this could be a different option for my get pushed challenge this week from JackieR which was to do a surface rainbow refraction ( ie not through water) you'll find it in bubbles, oil, shining light through some plastic/perspex. I know this isn't quite what you were after, but I did love the reflection anyway.
