Another vote here for using a 2 channel preamp with HT bypass connected to the AVR pre-outs. Here's a thread with a list of preamps with a HT bypass:
http://www.polkaudio.com/forums/showthread.php?90594-Preamp-with-HT-bypass
http://www.polkaudio.com/forums/showthread.php?90594-Preamp-with-HT-bypass