The marine grade plywood is used for the water protection. I’m sure a cabinet maker can do a custom one for you— with lots of poly for protection. I’ve read on here that people regret the vessel tops because of the constant splash. If you plan on installing in a heavily used bathroom, would suggest you do some research on integrated vs vessel.

This is interesting Liz. Sarah Richardson the Canadian designer says when putting in vessel sinks one doesn't have to be concerned about the top of the vanity which is why old dressers repurposed work for so well for vessel sinks. Doubt if you have to go custom. Look at IKEA, any bathroom store..heck I just googled and got a page full of vendors.

Thank you both! I’ve read mixed reviews about vessel sinks. Some people say they love them and never have water on their counters. Other people say they’re a nightmare. I wanted them on our master bath, but I think I’m going to only do the powder room in case it is a splashy sink. I think the sink shape and size, faucet type,
And water flow rate all factor into whether it’s a great sink or a splash fest.

Have the cabinet custom made out of a wood-look Corian. I had a larger vessel sink and consider myself a splasher; no problem.

Thanks, Joseph! I didn’t even know that was an option! I’m guessing it might be pricey, but I’ll definitely look into it!