best deal on an affordable tube pre-amp with HT bypass?

Check out Jolida Fusion, $1350 new. Have not seen one come up on AG used. I have one and think it great.

Quicksilver makes one at $1000 new. May need phonostage. 

If you are handy with soldering and such, I recommend Transcendent Sound Grounded Grid preamp, just $499 for the kit. Has three 12AU7 tubes, and can easily be made to have a HT pass-through.

I built mine with that feature, silver hookup wire, Bent Audio remote volume control, NOS Amperex tubes, Clarity Caps output caps,and Goldpoint stepped attenuator and selector switches. A little under $1000 with my upgrades, but it sounds great.

The bone-stock builds are supposed to be quite good as well, and are an enjoyable project.