re: Anywhere to get kaffir lime leaves in BR?

"Regular" limes (which are most often Persian limes) aren't nearly aromatic enough. Key lime zest is a bit closer. Again, lemongrass is much closer to the pop of kaffir lime leaves. You could also try a local nursery--citrus trees cost around $16, and you could keep it in a big pot (though you'll need to bring it inside during extreme cold).