I must say that isn't a very common need, I'm curious what your workflow is that you require this? If you had a control surface you would essentially have this because you can grab the bass fader, or push the bass track select button. The Euphonix controllers will let you permanently set a fader to the bass track if you want. But for key commands to select specific tracks - I can't say that I've seen any DAW do this.
A second keyboard as a controller just aint gonna give you more than your MBP mouse/keyboard in any DAW
Pony up for a controller of any kind,for sure,the Euphonix would be stellar but maybe those tiny Korgs would be worth a look.