Oh, for integrated amp that has HT bypass. The idea of an "HT bypass" is to completely bypass anything in the preamp, including any tone management or crossover. The unit will typically connect the input wiring directly to the output wiring and not even go through the preamp stage, therefore letting the source AVR or HT Processor do the bass management on its own.
However, there is an existing solution that might help you. The Parasound units, both the integrated and the P5 / P6 / P7 preamps, have a bass management crossover as well as full HT Bypass for left/right and subwoofer channels. This allows you to still use a AVR or HT Processor and connect the 3 left/right/sub outputs directly to the Parasound unit for straight passthrough.
The Parasound integrated is a combination of the P5/P6 preamp and a version of the A23 amp with a larger transformer. The Parasound amps have a warm sounding sonic signature (definitely on the warm side of neutral). For the preamps, the P7 is the best unit due to better analog circuits and better power supply.
When you use the Parasound units for normal 2-channel listening (such as from a DAC or turntable), the Parasound unit will do the bass crossover management and send separate signals on the left/right and subwoofer outputs. This gives you the best resolution possible.