[duke36]

It appears you may have come across Marshall Lewis' article from decades ago in the Restorer Mag. He used 1/8" marine ply. and soaked it in water. Sometimes, one can score the back side curve with a table saw to help. I have an orig. trunk from the early 30's that has 1/4" curved ply.for the top and is very sturdy. Another option may be to try mahogany door skins or similar from the home stores because the adhesives may soften better than plywd. adhesives.