i couldn't find the previous discussion either.
but no walls, completely open building is still a building. the absence of walls does not mean there are no openings, as the space between the roof and the floor is the opening. so the magic is defining the "wall", allowing the roof to "project" beyond, per the distance to property line.
per Table 602, your suggested Type V-B structure, "exterior walls" need to be protected at anything less than 10' from the property line. but the roof can project beyond per section 704.2. per table 704.8, un-protected openings are Not Permitted at 5 feet, so you can project 12" into that. so the roof edge can be within 4 feet of the property line.
so set the columns at 10' from the property line, and the roof edge at 4 feet, and you will have more area than what you proposed above.
now if someone has some grand ideas about buildings with no walls, to be closer than that, please speak up as that's what i'm trying to solve. thanks!