You might be interested to try this. I've not tried, so it's up to you if you want to take the risk.
Edit: Works - see /u/Asmero 's comment below.
Using both card and Paypal doesn't work for non-U.S. accounts, even if you use a U.S. address. Gift cards may work though as there's nothing to verify the address then (assuming it doesn't force you to input financial details anyway).
Amazon.com has GameStop Gift Cards with e-mail delivery. The only problem is that there's a minimum $25 amount.
For Amazon.com you can put in a valid U.S. address and it won't check it against your card details. You can buy digital stuff from there without issues.
You could then try to use the gift card during the check out process.