I think they bought the old Yokohama motorcycle tyre plant originally, but have since done their own thing.
I have used a few sets of them in ST1300 sizes on the ST1100, as have a few other ST11 riders I know. The landed cost from jake Wilson is around $220 a set, but I buy in 3 sets at a time.
Typical life is 15,000kms plus, upwards of 20,000kms so far. I have found them as good as any other tyre in the wet and dry, which surprised me. Originally I was only going to use them as a saving to pay for the tyre changing equipment I bought, but I continue to buy them because they work and last. They do feel a bit more sporty and ride slightly harder than tyres like the Pilot Road 2, but cost 30% less from the same place. I got 17,600 from a set of PR2s, they did not feel any better than the Shinkos and towards the end of their life felt worse due to the way the dual compound wore in a strange pattern.
The Bridgstone BT023GTs are now available at a good price as well from Jake Wilson, and not that much more than Shinkos if you want to stick to a better known brand