The closest thing I have come to original Art wason the Atari Historical Society (I think that was the name of the website), however I have not been able to get onto the site lately. I remember seeing the original Bezerk cover there.
The only other leads I got was from page 2 of the Missle Command Instruction booklet. There is a small illustration with a signature. The first name is Steve but I can not quite make out the last name. (Handrick,Handrich,Hendrich,etc...) I checked out numerous spellings online but to no avail.
There is also a signature on the cover of Surround, but it is too small to see.
-Chris