I'm also interested in durable, walkable panels. I think the Tiny Watts people have an inside track to a supplier but they hold that info pretty close. They do exist. I think you could probably source through Tiny Watts. I'm in Canada so it makes things a little more difficult.
Will, any chance of putting together a Tesla DIY blueprint? Alternatively do you consult on system design? I'm in the beginnings of a sprinter conversion. I plan on induction cook top, small tv/monitor, water pump, Espar and lights for all the typical consumers.