Originally Posted by cabmando

Likely reason for difficulty of a double door or wider door is the header that would be required along with sufficient framing at the corners. I remember helping my brother build his garage and thinking "this is bullsh.t" The way we had to frame the wall with the overhead door struck me as nuts but he's in a "hurricane" area so the header went from wall to wall IIRC and there wall had extra framing as well.
I would guess that width of the wall is his limiting factor in doing two doors with sufficient stud framing for code.