My design (a bitaddress.org fork) has fairly large QR codes and more importantly, whitespace around them which is often the sticky point for scanning. Give it a shot.

https://bitcoinpaperwallet.com

https://bitcoinpaperwallet.com/images/front-back-sample-big.jpg
https://bitcoinpaperwallet.com/bitcoinpaperwallet/images/finished-sample-sealed.jpg