Well, some midnight Googling and I came across these:
https://www.sampsonstore.com/neovision/condom/-Sagami-Original-0.02-XL-size-3's-Pack-PU-Condom/details.is?product_id=4373
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Dedication in Every Millimeter: 3mm Wider after 10 Years of Effort
Sagami Team invested 10 years time and successfully developed the world's first Sagami Original XL-size PU condom, measuring 61mm in width, and 3mm wider than Sagami Original L-size condom. You might think, "Only 3mm and it took 10 years?" Yes, the challenge in engineering an XL-size ultra-thin condom is huge, and ensuring maximum quality in millions of productions without a fault is a mission impossible. Yet Sagami accomplished it! The 3mm wider took the brand 10 years of effort.
Sagami's pride, Sagami Original 0.02 XL-size PU Condom is making its debut in Hong Kong. It is hoped that Sagami Original XL-size PU condom can bring more unforgettable intimate experiences to couples of diverse cultures in this vibrant city.
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So I guess Sagami spent 10 years to make an XL size and then decided there wasn't a need for it in Japan? I decided to take the plunge (only 3 in a box and it's around 2,000 yen including shipping) and see if they're what I've been hoping/looking for.