Yip, my resto team had a real good look at the existing handles, solid billet or steel with woodgrain screwed in. The wire can by placed in a cut grove along the steel piece but towards the bottom of the grip that woodgrain gets mighty thin and you could run the risk of breaking it.
Then of course if you do get it to that stage where to from there? You can't go down because you'll run into the button mech and past that point the wire will get tangled in the gear selection detents. It "can" be done but would take a lot of man hours and a lot of fine craftsmanship.
I just went with the floor shift toggle/button with a red boot around it signifying that it's the "GO" button!
When harms do create the button shifters (estimated 2-4 months away) I'll buy one of those grips and be set!
Cheers.