I made one once much larger than that to flatten the top of my nearly 8' long workbench (laminated together from 2x boards). Cost me a couple of dollars worth of ply. I stood a sheet of 3/4 mdf up on either side of the bench and cross braced them to stand up and be rigid and made the sled to ride on top of the edges. Not nearly as pretty but just as effective.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.