I've just finished a demo for Chris Hein Horns - Vol. 3 Muted Brass. It can be found at the link below. This demo features 4 Harmon Mute trumpets, 3 Cup Mute tenor trombones, and 1 Cup Mute Bass Trombone. The rhythm section is all Cakewalk TTS-1 for the sake of expediency. Anyway, the focus should be on the brass section. The library is scheduled for full release in April 2009 but will be on display at NAMM.