Here's some pictures to illustrate where I'm coming from on the "width problem".
My garage is 20'x20' with a poured slab floor, 6-ish inch high concrete footings along the perimeter, wood-framed/stucco walls, 9.5 foot ceiling, truss roof, and a 16' wide double-door. I can't speak for other parts of the country, but it's typical for standard single-family houses where I live.
The lift is on the left side of the garage, looks like this. It's a BendPak HD9-ST, the narrow, short (length), short (height) lift -- basically the smallest 4-post they make:
There's about 1 foot of space between the footing and the post. That's enough to squeeze betwee the post and the wall:
(I really need to get around to installing that Tire Rack Tire Rack)
The right-side post winds up a few inches shy of the centerline. In theory, yes, I could move the lift slightly to the left to add more clearance, but if I do that then I'm losing drive-on width because it's now in the "shadow" of the 16 foot garage door. As should be fairly obvious from this photo, moving this post a foot further out means the Audi would hit the mirror trying to pull in.
The Audi could be maybe a couple inches further over than this photo, but as it is I'm close to rubbing the passenger mirror on the edge of the door pulling it in.
So that's the basis for my saying that a 2-post lift is too wide for a typical (where I live) home garage.
As for the question of vertical stacking, there are some things you can do to help with that. The first is obviously a high-lift garage door with a wall-mount LiftMaster 8500 opener.
In addition to raising the garage door higher than normal, this also makes it effectively "shorter" in terms of how much ceiling space it takes up because about a quarter of the door is still vertical. This means that if you have a car with a trunk, you can line things up so that the door sits above the trunk and doesn't take away vertical clearance. Miatas are good at this beacuse they're short. :)
Since my ceiling is 9.5 foot I have limited vertical stacking ability. The Miata is 44-ish inches high, the FD is 48-ish, and I lose about 8 inches from the height of the runways, plus the 2x8s that the Miata drives on to clear the rolling bridge jacks. That's 100 of my 114 inches. The lift needs to rest on safety catches, and the latches for those are every 4 inches. You also need to lift it 2 inches to release them, so that's another 6 inches or so of clearance gone. That leaves 8 inches -- there's room to lower the Miata one notch on the safety catches and still fit the FD underneath.
Overall shot:
So yeah, I'd love to have a 2-post lift, but it just won't fit.