The Real McCoys, The Strike Gold, Studio D'Artisan.

Here's a good introduction on loopwheeled shirts from Japanese repro brands.

http://www.heddels.com/2014/03/an-introduction-to-loopwheele...

Only some of The Real McCoys are loopwheeled sadly, and there's some confusion over which.

The Flat Head and Tezomeya are also other examples of loopwheeled tees.

Then... how can you really tell what The Real "The Real McCoys" really are?

RMC website is accurate. But some distributors like superdenim mislabel things a lot.

$100 for a t-shirt?

They're £58.33 plus £10.00 shipping which converts to roughly $100 US. I'm not that frugal, but Jesus this shirt better be tip top quality and last longer than 6 months for $100.

Are these western names used in western countries for Japanese products or so the names also get used in Japan?

The names are used in Japan. Some of these names (e.g., "Strike Gold") conjure up an old-school Americana. This is intentional. Japanese denim brands (who now make these shirts as well) are very reverent of pre-1960s Levis.

They use the English names in Japan. If you google for the Japanese official websites for these brands or even their products on rakuten.co.jp you'll see the brand names in English.

The magazine Free & Easy is all about these brands