Taking it easy on the engine upon cold startup is a good start. I rarely give my car more than a 60-120 second warmup, but I also drive it much more delicately until its at operating temperature. There is very little traffic near my house early in the morning so I can accelerate as slowly as I want. The engine is generally at operating temp by the time I get 1/2 mile out of my neighborhood.
I babied the engine for the first 200 miles following all the rules. After the first 200 miles or so, I tried to encourage the car to use more grunt and avoided running the engine at the same RPM for long periods of time. If I were doing any freeway driving, I try to acelerate and decelerate using my gas pedal as much as possible . I didn't necessarily beat on the car, but I didn't baby it either. I tried to keep the car between 2500 and 4000 RPM whenever possible and did run it to 5500 for short bursts during harder acceleration, usually once or twice per trip. Applying a load to the engine for short periods of time will increase pressure against the cylinder walls and help to seat the rings. When applying higher load to the engine, it is important to slow it down using just the engine rpm's. This creates lower pressure in the cylinders and increases oil flow through the engine to remove the particles released.
Even at 1500 miles, I'm not comfortable beating the engine. I will continue to take it easy on acceleration and vary the engine speed whenever possible probably until about 4000 miles. The precision in these engines is such that Toyota is comfortable allowing you to go 5000 miles before the first oil change. During the break-in process on these engines, the particles released are so small that I think Toyota is probably right, but I'll most likely change the oil at about 2500 miles just to be on the safe side.
As for the short break-in periods, I'm sure they probably work. I'm also confident that the Toyota engineers know what they're doing. I think Toyota promotes the 'longer' break-in periods because it is easier to damage your engine during a short break-in if you don't do it properly. Then again, they're making a car for daily drivers. Most of their customers are not automotive engineers that build racecars.