Pretty much the entire Mark Knopfler catalog is HDCD encoded, as are several of the Keb' Mo' albums. I know that one or possibly more of my Holly Cole discs are HDCD. As mentioned previously, the Reference Recordings discs are almost all (if not all) HDCD. I'm especially fond of From the Age of Swing by Dick Hyman--fantastic recording and unbelievable dynamics.
This website http://www.hifimusic.se/hdcd/index.php?p=base also has a searchable database.
This website http://www.hifimusic.se/hdcd/index.php?p=base also has a searchable database.