This is a good idea, just print the pattern on one side, pop it in the printer again and print the bills
Check out this printable back pattern I made:
https://casascius.com/billback.pdfCasascius, do you have a layered image file of this design? (xcf, psd) and a copy of the font used?
I really like it a lot. Since I am using a modified version of the BitPay design with my notes, the "print more of these:" portion would need to be changed for me. I have nothing against bitaddress.org it's just that my customers are paying a premium for printed coins and bitddress.org does not offer the desgin I added to RobKhor's printcoins project.
On a side note, Casascius, you are one of my bitcoin heroes because of the physical bitcoin implementations you have followed through with.