I'm looking for somewhere in the US that will sell me 15-20 iWatt
iW3610, or IW3612 LED driver ICs. They're used in the power supplies
of LED light bulbs.

So far, I've only found them at large industrial suppliers (mostly in
Asia), and at http://uk.rs-online.com. Unfortunately, RS won't ship
to the US, and their US partner site (Allied) doesn't have the part.