David Duchovny as Schmendrick

He does have the right appearance.
I'd also recommend Adrien Brody for the role, especially after seeing him in "Houdini."

Zach Braff

That could work :)

RIP
Jeff Hanneman
1964-2013

I feel like David is too old.. however, I think Eric Balfour would be perfect. He just needs color contacts. I used to want Elijah Wood to play Schmendrick (obviously not for the height), but because I thought he could pull it off. I could just see him as Schmendrick. But when I saw Eric on the TV show Haven, as the goofy criminal with a heart of gold.. I thought of him for Schmendrick.

How about Joel Moore?

"*beep* the law, i want meat"-Nightbreed.

You know, I recently stumbled upon an actor that I'd never heard of before - Lenny Von Dohlen - the moment I saw his face, I thought of Schmendrick.
The show I saw him in was from the early 90s (Twin Peaks).. and he's older now.. but he still has almost exactly the same face. His hair is white, but he's well-preserved for his age, and I think he could totally pull off the role of Schmendrick. He's also got a similar voice to the Schmendrick in the animated movie.
Check him out:
http://www.imdb.com/name/nm0902188/

Too old. I think http://www.imdb.com/name/nm0601376/ Joel David Moore would be a good choice, but even he might be too old. Prince Lir could be Clint Eastwood Jr. Amalthea could be played Anna Farris, maybe too old, but maybe Emilia Clarke.

Danielle Radcliffe?