abec, along with original novel creator, Reki Kawahara, was a special guest at Anime Expo 2014. Aniplex put a tight leash on both of their guests to the point that, other than abec's frog, there were no sketches. This particular sketch was featured in the AX 2014 charity auction, and likely because it featured Kirito from GGO that there was no competition for it.

After the auction, I looked around online to see if original abec artwork was common and could only find one other original sketch on a Japanese site. I assume that original abec sketches are quite rare.