I've heard the problem shipping internationally is, and this is coming into the us not just going out, sometimes the items will sit in customs for long periods and then they add on fees which there's no real rhyme or reason to how much they charge. So it's difficult to determine what shipping will be, and typically it's way more than expected which can cause some disdain from the buyer.
I'd be cautious, but explain very clearly what might happen just to stay out ahead of any non-payment issues, or negative eBay marks, etc.