Am I able to get a Visa or Mastercard that is based in Hong Kong Dollars?

I am a US resdient and would like to use my US address and contact for the billings and such, but my son will be travelling in HKG for about 6 months and I want to get him a HKD Visa or Mastercard, preferably via Citibank, or HSBC, or any of the other big banks in the US, Fleet is OK too, or must I apply via a HKG bank (but I would be an international resident). Do any of you do this for countries you travel to. As I am sure we all know using a USD card in the UK, for example, we get charged using a bad exchange rate, and then a fee to do the exchange on top of that. I want to avoid that.

Thanks for any insight.