Please excuse me if this is a silly answer and not what you wanted to hear, but Clickbank isn't limited to people in the US.
Clickbank does allow joining outside the US, but unfortunately for some the checks are just too expensive to cash (last time I tried it cost AU$50 and I still got the check back because the travel time meant it expired before they cashed it). After ending up so far out of pocket, I haven't tried again. Some countries are now approved for direct deposit payment (you can get to the list from their accounting policy) but even so you need to have received 3 paper checks within a 90 day period before they'll let you sign up for direct payment. I'm trying to meet that requirement now. If you post which country you're working from, that might get you a better answer. I know some of the Aussie ones, but they might not be any good to you if you're elsewhere.