3 point rear belts in a crew cab?

[1774btcrew]

I have been trying to get this sorted out for some time as I am not real comfortable having my kids ride in the back with only lap belts. Has anyone found anything that will work? I have tried several options. I welded in the inner upper plates. I had hoped that the Suburban rear belts would work but they don't seem to fit the curve of the floor right. When that didn't work I ground the rivets off my stock crew cab floor mounting plates and plan to use them with the Suburban belts. Does anyone have a cleaner set up that is more of a bolt in?