Thought I'd share these - the artist is @tomo_design_works on instagram, that's the only way to find him that I know of.
He has a huge range of Z900 related art, worth a look just to see his range - he will draw a particular model Z, in each of the factory colour ways, then change pipes wheels carbs etc, totally awesome.
He offers t-shirts of some of his work too.
I got these from him a while ago, quality heavy t-shirts, and excellent detailed art, the front also has a small version of the back image. Colours are way more vibrant than my photos show too.
There is no online shop, just DM back and forth ( very little English language) and a direct bank transfer - so it was a bit of work, and waiting time as they are done to order, and had to be trusting, but they had freight tracking so once they were on the way it was a relief. I got 4 in an attempt to make the freight worthwhile but they still cost me a bit over $100 Aussie dollars each landed. I'm not one to spend that much on a shirt normally but these are awesome and super cool.
Tomo was very helpful and had a good system his end, he rides a kickarse Z900 also