I have seen this done before and could NOT resist doing one! I had bought this broken chair for 50 cents at a yard sale.
Since it had been broken the tape had to come off then My Dad and I measured to see hao wide we wanted the shelf. The used a hack saw to remove the excess. Then reattatched the fromt scrolly piece to the front of the shelf then added the seat back on.
Then a couple of coats of paint and distress also adding a scrolly piece to the back for some extra detail.
This is your end result something affordable and unique! Hope you like it!