I'm going to say this is Ray Palmer, because the costume reminds me of the one future Atom wore in the JLA Rock of Ages arc, but that's just my best guess.
"Phil Hester is soooooo generous. He did this sweet sketch for my brother..."
Sunday With Hester
2007 Wizard World Texas Convention Sketch by Phil Hester @ The Idol-Head of Diabolu
2006 The Question Mo-Kan Comics Conspiracy Commission @ DC Bloodlines
2005 Wonder Woman Meets Swamp Thing Commission @ Diana Prince
Zatanna @ Justice League Detroit