Cartoonist and Comics Journal columnist Frank Santoro is about to begin a second round of correspondence courses for comic book creators. (There's an application deadline of May 30th.) Santoro is the guy behind Cold Heat and Storeyville, and he's recently been featured in Sammy Harkham’s anthology series Kramer’s Ergot. His approach to comic layout is rooted in old school printing techniques and renaissance-era “golden ratio” compositions, and his actual illustrations are based less on black lines and more on building colors in layers.
For more on Frank, I recommend this series of Layout Workbook posts, which cover a lot of his ideas about grids and the harmonic points in compositions.