Yes, I have seen that and yes, it can be done, however that Official LR unit as shown as STC50039 is expensive, if you can get one these days and quite honestly very unreliable. The fit isn't easy either.
The switch can be purchased, but, ain't there always a but, it's not a latching type switch. So that's why it has to be modified with the switch from a the cruise control and then swap the fronts.
You'd probably be best to start from scratch, rather than to try modifying the existing circuitry, for all the reasons already expressed, so you'll probably have to get a connector to fit on the back of the switch too.
Once you've got all that together, installing the system on that website page should present few problems to someone with a bit of experience. The information you'd need is on that page, from the picture of the burned out box onward.
The circuit which I built uses the proper switch, which as I said is non-latching so I built a little box of tiny relays to make it electrically latch and unlatch or toggle as it's called.