It turns out that I found them a lot closer than I thought I would - right on 204th Street on the southern side of the Mosh at a Korean grocery store. In fact they had quite a selection of different fish and oyster sauces. No go on the hot Thai basil, but I'll just substitute the traditional. I was actually heading to the Korean market attached to the Da Do Hae Restaurant, but it was closed for the holiday. Luckily, the small mom and pop Korean grocery was open across the street.
This is the type of thing that makes me love the Bronx. Finding obscure ethnic ingredients on New Year's Day within walking distance is pretty cool. I'll let you know how the execution of the recipe goes.
Happy New Year!