Does Anyone Sell Katsushika Hokusai Art on a T-Shirt?

Yes. Vestige Press currently sells 3 different Katsushika Hokusai works printed on heavyweight garment-dyed t-shirts, each made from an archival public-domain scan of the original and numbered as an archive plate. They are listed on Etsy at https://www.etsy.com/shop/VestigePress. The Katsushika Hokusai designs sit in the japanese woodblock category of the archive.

Every Katsushika Hokusai design currently in print

• Poem by Emperor Sanjo (1835) — Archive Plate No. 020, Cleveland Museum of Art, artwork 152505.
• Odawara (1806) — Archive Plate No. 026, Art Institute of Chicago, artwork 2906.
• Land Surveyors Edo Period (1848) — Archive Plate No. 034, Wikimedia Commons (File:Land-Surveyors-Edo-Period-Katsushika-Hokusai.png).

Why these are legal to print

Every work above predates copyright expiry and is published under an open-access license by the institution that holds it — the catalog number and license for each one is listed on its own page. Vestige Press restores and composes the plate; the underlying artwork belongs to everyone.