Hi,
This is a pretty cool idea and I found an easy way to implement it using the google charts api to generate the QR code image, so I implemented it this morning. Its in the source code repository now so it will be in the next release. You'll be able to add this in the layout.master of your printerfriendly skin:
<portal:QRCodeImage id="qr1" runat="server" AutoDetectPageUrl="true" />
Best,
Joe