I am looking for very narrow drop bars. size 30,32,and, 34 for a road bike custom is acceptable .
I haven’t found any bars of those sizes in my searches. Best way probably to contact one of the carbon builders that moulds stems to bars and get them to take out the centre of the bar to reduce width, then fuse a stem on so the join can be overbuilt. Not a cheap way of doing things though it does allow selection of reach/drop.
Trek and I am sure other manufacturers have small road bars for the tiny-kids bikes. You will need to go to the dealer to order the part.