There's a band called Pianosaurus... no longer a band, that was a band entirely made up of toy instruments. I never successfully tracked down their music and never heard any of it at that. If someone finds their stuff let me know.
this reminds me of that band, SELF. they had an album called Gizmodgery. it was all really cool songs done with toy instruments, along with a cover of "What a Fool Believes." solid gold.