Welcome to TVPaint Community forums !

I'd like to assocate tools with particular layers, so that the tools automatically change when you switch between them. Having a blue sketch pencil, a black outline pencil and maybe a fill tool associated to different layers (maybe with different erasers on the opposite side of the pen) would be great. It'd help me keep track of what layer I'm on a bit more as well.

Ideally, I'd like to keep track of this from a little custom panel.

Is there a way to do this already?

not a bad idea.
though it might be complex to implement.

perhaps it is even possible now using a custompanel with some action scripts...?

I can give you a script that does it, but it works in the way that you set custom buttons for tools, then each button selects a particular layer too.
I use it alot and it's very time saving.
you want?