Tamiya reboxes Italeri kits for the Japanese market. I have a Tamiya boxed OH-58A, but its all Italeri plastic inside.
You might try some of the Japanese based online sellers, like Lucky Model and Hobby Link Japan. Lucky Model had the "Tamiya" OH-58A when none of the US based shops had the Italeri kit.
Italeri did several versions of the Bell 47 in 1/72. Unfortunately they are getting hard to find even on ebay, I know because I've been after the USCG HTL-4 version myself for the past year.