anyone ever done it? transmission and clutch must make it impossible huh?
it can be done with the crank in, but you need something that can push the upper bearing shell out without damaging the crank journals.
I have done mains in the car by removing the trans and dropping the crank, not an easy job by any means.
Yuppers.
My favorite tool for this is a plastic putty knife cut to the same width as the bearing... push on the end of the bearing without the tang and they literally swing around into your hand. Some folks use an old bearing shell.... the idea is something soft... although truth be told the crank journals are actually pretty darn tough.
I also use a screwdriver that has the blade flattened on a grinder as a press to ensure the new bearing shell is exactly flush after it as been spun on.
I've used a flattened piece of copper to push them around.
Last post I saw with a guy doing this;
he couldn't get number one out,..
until he loosened the timing belt.
Yuppers.
... although truth be told the crank journals are actually pretty darn tough.
I would do the rod bearings, but forget the mains, unless it has well over 300K miles / 500K km. I have little indication of mains wearing on really old engines.
I agree, my machine shop guy said that he's never seen a watercooled VW engine need mains that didn't otherwise have any damage. Though the thrust washer/bearing will normally go way before the mains do, especially if it is not installed properly or crank endplay is off, or if people like to sit at red lights with the clutch held in.

Brendan
I agree, my machine shop guy said that he's never seen a watercooled VW engine need mains that didn't otherwise have any damage. Though the thrust washer/bearing will normally go way before the mains do, especially if it is not installed properly or crank endplay is off, or if people like to sit at red lights with the clutch held in. 
Brendan
I especially like the guys who slip the clutch on a hill to hold it there at a light.