Vertical vents for high efficiency forced air?

Living in Chicago, in a 3-story 6-flat ~ 120 yrs old.  City ordinances now mandate > 90% AFUE furnaces, but currently each unit has a "mechanical" room in the center of the unit, where both gas water heater and gas forced air furnaces (nom 80% AFUE unites) vent to a common chimney (previously for basement boiler?).  Makeup air to mechanical room is via wall louvers fed from basement area, but it is a *very* loose building.

My question is: Are there any > 90% forced air units that allow vertical vents(w/ makeup)?

Last I checked (~ 10 yrs gao), > 90% units required coaxial (makeup in/flue gas out) horizontal venting, sloped to outside, but Chicago had taken a hard-line against icing/icicle hazards.  Also, there's enough room, but running duct laterally would seem to require ripping out someone's floor or ceiling, not to mention making pretty big holes in a three-leaf brick wall.  Just looking for possible, better solutions.