I saw that video a few years ago. I was thinking of doing that to my Yukon, but I just ended up buying an '03 Suburban instead.
My concern with welding those into the floorboard is the amount of support the floor of the truck can provide. I'm no expert, and I've never really looked under there, but if you were to simply weld it into the floor, how well would it hold up in the event of a collision with two kids seatbelted in?