I, too, would like a similar feature. In my struggles to find a good hotkey-governing plug-in, I'd like for winamp to allow me to control what the hotkeys are and do. I use a dvorak key arrangement, so the standard zxcvb hotkeys for playback are no good for me:
I'd also like to input 2 sets of hotkeys. One for while winamp is directly being accessed. And another set for global hotkeys. For example, I'd like for ";" (your Z key) to be "previous" while Winamp is directly engaged. And I'd like for "shift + ;" to be "previous" as a global key. This seems like it would be an easy process (I'm hoping.) So there's that. Thanks for the consideration. And please speak up if you'd also like it. I think strength in numbers may help encourage the development.