Someone recently suggested checking out paymate.com. Yes, they're international and best of all, they say they're committed to reducing unfair chargebacks that PayPal customers have become so accustomed too.
I've tried Moneybookers, but they're a little iffy (bad reports about account limitations). So next step is definitely PayMate.com. Fingers crossed.
1) We don't have a lot of money to build this thing (Samurai).
2) We are in Chicago, IL, USA. We are familiar with the laws and customs in Chicago. We speak the local language.
3) The laws and language from Chicago, IL, USA happen to be more or less applicable across a very large and fairly wealthy single market. Merchants near Chicago, IL, USA tend to be in their offices when I'm awake and my kids are at school.
4) Let's start with that market and expand to others once we get the resources to do so.
Honestly, American startups don't purposely omit non-US markets. But when you're trying to get to profitability on limited funding, this train of logic will come up and you really need a good reason to decide to pick an unfamiliar market to start.
I'm not sure "there are plenty of viable US options" is entirely accurate. I've tried a bunch of options, and found them all to suck to one degree or another. We're currently using PayPal Web Payments Pro...it also sucks. But, at least their pricing is sane and comprehensible, and I don't hate life when dealing with them fro chargebacks and such (it's all on the web, and no faxing is involved, as was the case with every other merchant services provider I've ever tried or contacted, including supposedly modern options).
Merchant services is shockingly archaic in the US. It may be even more shockingly archaic in the rest of the world, but it's definitely not good here. I'll definitely look into this when it becomes available.