Amplifier with the best Bass?

I thinking to have a bi amping system. One amplifier will be treble/mid and the other will be bass.

The amplifier for the bass should be good for Bass. I am thinking in a Bryston 7B ST. Do you know any other amplifier with an extraordinary good bass.
If you don't mind an older amp, the Krell KSA 250 was a bass champ.
Class D amps have best bass and best to biamp with. Wyred4Sound street or similar may save you lots.

You need to read this post,

Using two different amplifiers is not a good idea.
Although I was able to successfully bi-amp as you wish to for years, I had an outboard crossover with level controls, the speakers were designed for bi-amping and I got lucky, as it took a few tries to find the right amplifier combination. So I have to agree with Tis49, you should use the same amplifiers if you're going to do it, or else get some amplifiers on loan that you could try it with. I also would not do it unless I had an external volume control/attenuator to match levels of the two amps. The gains in bass definition can be more than lost by the lack of coherence and difficulties in level matching.
Depends on what type of cross over you are using. If electronic crossover with sufficient gain control for the bass amp, then you will have no problem. In other words, make sure the crossover has impedance matching characteristics so that you can match the gains of the amps.

I would check out Krell or Plinius.
Get two pair of the Wyred4Sound Mamps. You will be good to go.