We were with some GMC people last weekend. And it was mentioned that one person wouldn't leave till the engine was to full operating temps.
=> There nothing good that happens to in an idling engine.

It's true that there is less wear at full engine temp. But that temp is reached much faster while driving.
=> In my durability dynos, the rule was always to stay under 1500 and 15"Map (~14" vacuum) until lube oil it 100°F. This never took very long.

As there is more fuel burned while on the move. Thus the engine has more BTU's used up in the process. The cylinder walls, an pistons have had 2000 degrees put to them. As to the oil getting moved around. In one minute. The oil filter, and all oil passages were full to start with.
=> Whether the oil passages were full or not is an open issue and depends on the engine and how long it had been sitting. It can take 30 seconds to a minute for all the places that get oil to actually get any after a long sit. That 100°F is never very far behind.

The oil pump has delivered about another 6 qts to get every moving part lubed. The engine has had the crank rotate around 700 times in that minute.. I'm sure there are lots of thoughts on this one. I use the one minute idea. One of the things that help these engines last so long. ( As long as there maintained properly.) Is you don't use them for short trips. Thus less cold starts per mile.
=> You are very correct about cold starts being tough on every thing. This is why capital engines (like it ships) are kept hot with heating systems when not actually running.

As a interesting side note. The 403 piston travels less feet per mile then a 455. So does a 403 piston/rings last longer?
=> Hang on tight, here we go....
Piston travel is a definite issue, but it takes a back seat to BMEP (Brake Mean Effective Pressure). BMEP is what makes the force to push the piston so then engine makes torque. More BMEP is more load on the rings.
The larger piston 4.351 (403) vs 4.126 (455) would make for lower BMEP at the same torque,
BBUUTT
The shorter stroke 3.385 vs 4.250 means it takes more BMEP for the same torque output.

Bob Dunahugh 78 Royale.