Shopify is really missing out on an enormous market in Brazil! It is one of the fastest growing e-commerce markets in the world, and there is no option like Shopify here. I am an American living in Rio de Janeiro, setting up a new business, and desperate for integration with a brazilian gateway. Jonathan, please let me know if your team would like to discuss this issue with me further. I am happy to help in any way. But really, you guys should realize there is an amazing opportunity here for you!
I agree with Robert. You're missing a huge market in Brazil. E-commerce here has grown 29% in 2012 and we do not have a shopify clone, nothing even close to this. It's only a matter of integrating 2 huge local payment gateways (MoiP and PagSeguro) and Kabum!, you'd have a LOT of Brazilian customers in a matter of weeks...
I also suggest CIELO (gateway, lower % fees).
It would be GREAT if Shopify could implement recurring payments/recurring billing and transparent/express checkout with those gateways, as it's a trend here. See http://www.manpacks.com recurring billing model for reference.