I had my music collection on random tonight and fell across this and I had to share.
Diablo Swing Orchestra is a Scandinavian band. I hesitate to call them metal because the range of styles they imitate are fairly wide. On their first album, The Butcher's Ballroom, they manage to include a waltz, a flamenco style piece, some peices on odd time signatures, and a BIG BAND piece. In a metal style. It's completely nuts and I love it!