I've found this to be the case, is that a facet of Selvedge jeans being made mostly for the Japanese market?
Not really. It's just that at the high end of the "younger" market, there is usually not that much demand for sizes past 36, the most popular sizes being distributed around 32 (so 30-34 are most common). I think that the APC jeans, the standard model of which is sized at least 2 sizes above the stated, is probably your best bet. Try the Rescue. And the 36 Nudie RR may fit too - if they are a *little* tight to begin with, remember that denim stretches considerably with wear.