Not with a carpenter, but I think my ILs made their own. It is just made of a batten of strong wood fixed on each side of the stairs with a slot cut in, and a big rectangular piece of board that slides into the 2 slots. It works very well at stopping kids going through, and when they don't need the gate they just remove the board. And they have stained the wood to a similar colour to their stairs and banisters so it doesn't look too bad either.
Also the way it works on their stairs, an adult can step over it without having to remove the board (only just though, so a child would not be able to) which is quite handy, but that depends on the height and angle of your stairs I think.