Do you have part numbers for any of the Atlas or MTH cars you listed?
MTH has a good search feature on their product locator page. You can search the Premier line for Twin Stacks or Husky Stacks and get several pages of results.
Atlas likes to hide their past products from potential customers so they don't have a functional search feature to their web site.
Atlas have made half a dozen production runs of Gunderson Twin Stacks. Change the last digit for the 3rd and following runs.
Only one production run of Maxi IVs has been announced by Atlas so far.