I'd seriously consider looking at an A/V Reciever. The Onkyo 7.2 channel recievers have all the features you are looking for and give you bi-amping capability using the surround channels. They have zone two capability as well.
Onkyo TX-RZ610, Onkyo TX-RZ810 are on sale now as Onkyo is changing models. I just picked up the RZ810 from Crutchfield yesterday. I have not set it up yet, but I am using it the same way you are but also using the surround capability. I'm using the front preout and an Onkyo M501 amplifier to bi'amp my front speakers. I'm really interested in the Music Optimizer function on these amps which is said to enhance the sound quality of compressed music files and Bluetooth streams.
I think the Yamaha R-N803 could also meet your needs.
Onkyo TX-RZ610, Onkyo TX-RZ810 are on sale now as Onkyo is changing models. I just picked up the RZ810 from Crutchfield yesterday. I have not set it up yet, but I am using it the same way you are but also using the surround capability. I'm using the front preout and an Onkyo M501 amplifier to bi'amp my front speakers. I'm really interested in the Music Optimizer function on these amps which is said to enhance the sound quality of compressed music files and Bluetooth streams.
I think the Yamaha R-N803 could also meet your needs.