I've found that online marketplaces specializing in automotive parts are great. They often feature vendors who specifically deal with imports like kei trucks. Regarding shipping Japanese kei truck campers to the US, yes, it’s definitely possible.
Just be sure to check the import regulations and maybe get some help from a company that specializes in vehicle imports.
Also, while searching for kei truck components, I noticed listings for used bulldozers for sale on the same sites. These marketplaces really do offer a wide range of vehicles and machinery, which can be super helpful if you’re tackling different kinds of projects.