If you can find one for sale on a Japanese retailer, there are third-party proxy services you can use to have it shipped to the US. IIRC some are platform-specific (like services for Yahoo! Japan auctions), and the proxy obviously adds to the total price, but it's all legit. I've bought a fair bit of stuff through proxies.
You can use either a forwarding service where you order yourself to an address with a personal code, or a proxy buying service which does the ordering for you.
Unfortunately it's been about a decade since the last time I had anything shipped from Japan, so I don't remember which proxies I used :(
If you're looking for recs, I'd recommend trawling some of the subreddits for figurine collectors or garage kit hobbyists since they're both groups that employ proxy services quite a bit. Any type of otaku group really, lol. They'll almost certainly have some stories to share about good/bad companies.
