Best AV receiver to use as an AV pre amp

I Come in Peace . . . I recently changed over to av receiver from separates although I thought there would be a downgrade in 2 channel sound. So I went from the Integra Research RDC-7.1 pre-processor (struck by lightning) to Pioneer Elite SC-68 using same front amplifiers. So far, I am satisfied with the quality of the two channel sound (actually pleasantly surprised). However, as most of us suffer from 'there has to be something better out there' fever, I am entertaining the thought of inserting a stand alone 2 channel pre amp with bypass. But I could be happy sticking with Pioneer as it does have superior dacs and is well engineered, not to mention the best internal surround amps

Is there a slimline receiver that would free up the space needed for a two channel preamplifier?

i have a mcintosh mx132 h/t pre-amp tuner for 2 chanell listening paired with a mcintosh amp. is this ok?? i like it.

This is an old thread but I'd like to know the final resolution from OP.
Currently aventage series from Yamaha claims to have really high end preamp and DAC. 

     I think zd542's post way back on 1/26/2013 contained all the answers the OP needs to answer his original question.  That was 5 years ago but zd542's advice is still valid today.
    Due to the OP's insistence on only using an AVR for 2-ch music and his insistence on not utilizing a high quality separate preamp with HT Pass Thru, however, I seriously doubt the OP has improved his system's 2-ch music performance unless he followed zd542's very good advice.
    My thought is "you can lead a horse to water but you can't make him drink"
  Tim