Make a welded steel frame out of 1-1/4" square tubing of the same design as your existing wood leg structure and then cover the tubing with 3/8" thick wood on all sides except the side that touches the under side of the table. You will have the strength of steel and the outside will be wood. You will have a strong frame and the look that your customer wants. Your budget will take a hit unless you can pass the cost of the new steel & wood frame along to your customer.