Does anyone know where the 'W' for warpgate selection hotkey is controlled? I've looked most everywhere except every sub-dialog and the only reference I found to it was in the strings editor. I'm interested in created another global hotkey with requirements.

Isn't it in the "Hotkey" field of the "Button" tab of the Data Editor?

....No. I'm talking about the button that appears off the command card in the lower right. It has no button under buttons.