Did these guys inspired by the Wacky Races, of course, and the post apoc interpretation of them here: https://imgur.com/gallery/3OIXq
I haven't stat-ed them up yet, but that should be pretty straight forward. Making them balanced might be a different matter.
Don't have Dick Dastardly yet, but have found a mini on ebay I think will work for the Mean Machine.
Edit: Finally got round to the Mean Machine