The wood used in framing old houses is better than almost all of the
stuff used today, and plaster and lath also do a bang up job of
keeping things aligned, so the old framing is probably as true as the
day it went up.

Not in my house. Its balloon framed and was built around 1896.

The ceiling joists are all different widths, off by an inch or so. They
just notched them to make the next floor level and then had the plasterer
try to even it out.

What I did for the some ceilings was to add furring strips across the joists
and tried my best to shim them. In one room it was so bad I had to build a
drop ceiling with 2x4's wasn't a problem because I had 8 foot 6 inch
clearance.

The studs are the same. There is one stud that it looks like the plasterer
chopped at it with a hatchet to try to take out a bulge. There was still
one there but he just put the plaster down thinner.

For the walls a made up shims from all the old paneling. It was just shy of
an 1/8 so I just added as needed. To keep everything mostly strait I got a
8 foot straight edge and just worked my self around the room.

When they say they don't build them like they used too, thats a good thing.