About the arts...
The first Pico is not that good, but the feeling of the original is something you can't substitute.
The anime Pico, I admit I liked it (I like cute things!) cute and all, but not quite what I think would fit.
Zeebarfs one... I liked the last two ones, but yet I don't find that "Picoish" feeling...
The first one of Jose Ortiz is cool but, indeed the characters look too old.
The second of Jose is the one I liked it more (except the first one, the theet look odd), just what I think Pico is.
About Pico himself, I think the concept of Pico is a two sided coin: one side of it is a cute, inoccent little boy about eight years old. The kind of kid an old lady would love to pinch his cheek.
And, on the other side, when you make him angry, a crazy psycho who is not afraid of killing whoever gets in his path, pointing his gun to the head of his enemy and yelling "You've failed the test of life!"
Tom, I hope you don't mind that I include Pico in my comics. Don't worry, don't do that for profit, just for my personal amuse and because I lke the character.
What I would really like to see is Pico on a console, like AH. Call me crazy, but one can dream....