Notary Public in HK

Unfortunately, there will not be any. Notary Public cost are according to the Soceity of Notary Public charges, for Affidavit or Oath or Declaration type of document, the cost is fixed at $1,500.00 HKD per each document signed and witnessed. And for Certifying Hong Kong documents, the usual cost is $1,000.00HKD per each document certified.
Notary Public is a (English) United Kingdom system, other countries are only following the Notary Public system and try to adept to it.
U.S. Consultate is only a consulate which regulate H.K. document to be used in U.S.. If your document is used elsewhere, for example, Korean, you must first go to a Notary Public, then you will needed to go High Court for Apostille, then you will needed to go to Korean Consulate for further authentication.
For the about example, you cannot go to U.S. Consultate to complete the Notary Public process since the place that you will use the document is in Korean and not U.S..

2008-05-17 12:23:47 補充：
Not matter which Notary Public you go, if I must say, it will be the same.

I think you can contact the US Consulate General of Hong Kong; they have Notary Public on duty.