Maybe the wrong forum, but yesterday I saw the Dutch a capella-quartet Rock4 singing Queen-songs in the first part of the show, then they continued with the interpretation of the entire "A night at the opera"-album. Neither they imitate, nor it's a tribute-show. They were really good, they have a good sense of humour and it's a real good opportunity to hear tracks as "The prophet's song", "Sweet Lady", "Good Company" or "Mustapha" these days in a public space. The audience and I were enchanted. - Highly recommended!
PS: I was there and so was Thomas Zeidler. This man is everywhere! - Watch out link
Cheers!