I use leather for looks on some of my C&V bikes. You could give it a coat of proofide to make it last longer.
I run my mudflaps about 2" off the ground on the front, rear I am less concerned about.
I bought one leather mudflap, happens to be a Berthoud

But it was a lot thicker than I thought necessary so I used it as a pattern to make some that were a bit thinner. I have not played with laminating one yet.
Aaron