It's not a whole band, but in the Deathwatch RPG, the background of the specialist Black Shields (Marines who forsake their past and become wholly a member of the Deathwatch) strongly implies some Chaos Marines have chosen this path to return to the fold.
Also in the category of "we'll never get a black-n-white answer, but it brings up a neat possibility", with the implications in the HH novels that the Ultramarines absorbed the survivors of the 2nd and 11th Legions, I wonder what would happen if a group of Ultras discovered that not only were they not created from Guilliman's gene-seed, but that their gene-seed came from a Primarch who had done something so bad as to get his likeness scrubbed out where even Horus still stands?