I am a big fan of paper piecing (perhaps it's because of my coloring skills.... )!
Since I don't have a rainbow stamp, I turned to an online coloring page, where I found this image.
The lovely papers are from mel stampz (also free!)
Sentiment by me (computer generated)
cas-ualfridays ~ paper piecing
citycrafter ~ colors of the rainbow
papersundaes ~ CAS
totally papercrafts ~ rainbows
Thanks for looking!