This would mean a command that recognizes what track you have selected. There's currently a number of other commands, especially playlist selection and creation, that I think PT needs that would rely on this. I've read many requests here on the DUC for those. You'd think they'd be easy to implement. If you want a new track, the program knows which tracks you have selected, so that it puts the new ones right below it. Why can't there be a command for "new playlist in selected track" bringing up the naming window. It's hard to get a macro program to do these things, since it's a subwindow command in PT. If anybody knows of slicker ways of doing these things, we'd love to hear from you...
If you are using a kbd and mouse and you have Numeric Keypad = Transport, the 3 key is record ready if you have a track armed. If you have a control surface, the transport has record ready function.
perhaps not exactly what you're looking for, but interesting . Option+Command+spacebar. This puts PT in ext sync and record.You only need to hit the spacebar next to beging recording. This might come in handy if you need to assign a single key for a mouse button for example. Just assign the button to be a spacebar, and then a single clik and you're off and running.