The second piece was a fan request that was posted on to Deviant Art by sketchheavy. This piece was apparently done in trade for a guy named Lance, who requested a picture of himself with a bunch of his favoritest rappers:
Lance with Nerd Core by ~sketchheavy on deviantART
The artists in this sketch (from left to right) are Jesse Dangerously, Doctor Popular, Beefy, Lance, Frontalot (lower), mc chris (lower right), and I don’t recognize the upper two (possibly Dualcore?).