Here are a few more, all of which I think I originally found via posts on Skillman’s site:
Neil Kellerhouse: http://www.kellerhouse.com/ (Seven Samurai, et al)
Rodrigo Corral: http://www.rodrigocorral.com/ (Kurosawa AK 100 box, et al)
Steven Chow: http://chowdesign.ca/ (Pierrot le fou, et al)
Onur Çöçelli
Only I know the designer is Eric Skillman (www.ericskillman.com)
Do you know any other cover designer of the criterion collection?