How can I buy something in German if I live in the U.S.?
I live in the Netherlands and I am well able to buy from the German Store. My (original) iTunes Account is German, so there is no issue when I am in the German Store and logged in with the German Account.

It also works the other way around. Sometimes I want to buy things from the dutch Store. I have a second Account for this. When I switch the store, I also logout and login with the NL Account again.

The only catch: You need a valid payment method for each country. Otherwise I experienced no problem having a second account, nor location-based restrictions.

(Disclaimer: I only tested this with Apps, which were not available in all regions.)