Hi,
I really don't know anything about the gate you are describing, but have you considered building a half wall out of glass blocks?
It isn't a difficult thing to do, and your rooms(s) will still look open and light, but you will have a division there. Then, you leave an opening as if for a door, and attach a gate to a frame piece at the end of the glass wall.
You could even use a drill bit for glass, and drill holes on each side of each of the blocks in the top row of blocks (except the one closest to the edge where you attach the wood for the end). Get a bit large enough to string plain white Christmas lights through the blocks, and drill a hole in front of the block closest to the wall. Then, you string your Christmas lights through, leaving the cord hanging from the last block, and just plug it in. Makes an interesting light feature. Or you can simply buy the clear or colored rope lights and string them up under the top edge of the wood you would want on the top of your wall. Either way, it would look really cool.
I don't know any better way to do it without those big gates. I would be afraid that the child's fingers would get caught in something so wide, you may not notice him sticking his fingers in there when you are opening such a wide gate.
Good luck, would love to hear what you end up doing.