I'm using Acrobat Pro 7, and I can highlight in yellow.
I'd like to be able to also highlight other colors, while still highligting in yellow, just like to do when I'm highlighting in a hard copy manual.
Have a mode for each of them, a keyboard shortcut to turn each on/off.
Can the latest Acrobat Pro do this - or is there another solution from a 3rd party?
Yes, it can be easily done.
There's no shortcut for it, but if you enable Properties Bar (Ctrl+E) it will allow you to select the highlight color when you select the highlight tool.