Why doesn't this exist?
I'm envisioning something that's essentially the size of an armless, backless booster with some straps. The base would have an open belt path (like the CCO RF belt path, although the opening might have to be on the underside for comfort, since the kid would sit on it). It could use LATCH or lap only belt, or the lap belt of a l/s belt could go through the open belt path. It would require a top tether, and there would be nothing but straps behind the kid's back, plus obviously harness in front of the chest. Harness points would attach to the base for hips and crotch.
Would this not be awesome for travel and tight 3 across scenarios? Harness height would be limited by the height of the seat back.
I'm envisioning something that's essentially the size of an armless, backless booster with some straps. The base would have an open belt path (like the CCO RF belt path, although the opening might have to be on the underside for comfort, since the kid would sit on it). It could use LATCH or lap only belt, or the lap belt of a l/s belt could go through the open belt path. It would require a top tether, and there would be nothing but straps behind the kid's back, plus obviously harness in front of the chest. Harness points would attach to the base for hips and crotch.
Would this not be awesome for travel and tight 3 across scenarios? Harness height would be limited by the height of the seat back.