Static block covering main column and left sidebar (on 3 columns layout)

[Queuekstealia]

I'm trying to figure out how to some content covering the space of main column and left sidebar on 3 columns layout. Page have 3 columns in the first part and 2 columns with left sidebar in the lower part.This is my homepage, I don't need to have a new layout since the main page is the only one using the current 3 columns layout. What is the best way to get this design?
Is it possible to make it as a static block?