Rigadoon appeared in English applied to a dance (adopted from France); first printed reference found in 1691, a comment about an illustration: 'Satyr agst. French' Ep A2- "It is an original, I assure you, and drawn to the Life as a Limner could make the Features of one dancing the Rigadoon."

Rigadig- Herman Melville, in "Whale," (1851) has the statement "He would hum over his old rigadig tunes."

As S&R stated, 'ragadoo' was sometimes used as a description of a coat or wearing apparel. Canadian, but originally from the British Isles? The traditional Newfoundland song, "My Old Ragadoo" (In the Pockets of my Old Ragadoo), sung by Anita Best.

Not much help, I'm afraid.