In my experience of importing items into Australia from US some companies do not need to ship overseas as its such a small market and a lot of extra work especially if they dont do it on a regular basis, larger companies like quadratec have an DHL account, rockauto has a USPS Priority international account, both quick. you will find savvy just uses an international courier calculator when quoting shipping costs rather than using DHL or USPSI shipping labels.
Sometimes you can see the International Courier calculator at check out, thats the point at which I dont check out lol