Interesting Hybrid  Nonhybrid comparison
I was on cars.com just now comparing the civic hybrid and insight gear ratios to the regular civic and corrolla. Given the stock tire sizes, here's what I found:
At 70 mph in od/5th the civic hybrid is running at 1,958 rpm; an '06 insight is at 2,396 rpm; the regular civic is at 2,947 rpm; and the corolla is at 2,767 rpm. If you multiply the rpm by the length (inches) of the piston stroke, you get number that doesn't correspond to anything specific like actual piston speed, but it allows for a direct comparison among the four engines. The higher the number, the faster the pistons are moving in the cylinder walls. civic hybrid: 6,167 '06 insight: 7,692 regular civic: 10,138 corolla: 9,961 So we can see that at 70 mph, the pistons in the regular civic are moving 164% faster than the pistons in the civic hybrid. Now, according to my admittedly limited understanding of engines, as piston speed increases beyond the point at which it makes peak torque, the burn is actually chasing the piston down the cylinder. This requires greater and greater inputs of engery (fuel) inorder to make more power, which is why engines start consuming much more fuel as they rev higher and higher. So the rpm x stroke numbers I just posted above should be a major factor in the improved fuel economy of the hybrids, which just goes to show that if the manufacturers would give us 6 speed trannies with really tall overdrives we could see huge FE gains in regular cars. But, no, evidently they want us to think we have to pay an $8,000 premium for fuel efficiency :mad: Now, perhaps a straight comparison of the rpm x stroke numbers isn't a fair comparison, because the various engines might have very different cam timing and duration, as well as ignition timing. If someone knows more about this please chime in. However, I'm still struck by the huge differences in engine/piston speed between the hybrids and nonhybrids. 
Naw, I think that your comparison is pretty fair. I think they just don't want to have a car the market perceives as sluggish. With the Hybrid they can have the engine turn over at the slower rpm and still give users the feel of power, that they feel they need.

Do you have the displacement numbers for each engine? You've basically made an offset comparison of linear distance traveled ;)
I think it would be interesting to compare engine speed to surface area displacement. I've normalized your figures above to show how close everything is and did a percent gain on all compared to the civic hybrid. Code:
normalized % Gain 
How did you calulate piston speed? It is normally referred to in the total distance a piston travels in feet per minute. Your #'s seem too high to be in ft/min and too low to be in inches/min.
The aluminum limits the feet/min a racing engine can have its pistons survive and anything beyond about 5200 ft/min is considered unhealthy. I think you'll find that at 2900 rpm the standard civic is still well below this amount, but at redline is probably approaching it. Some racing engines go well beyond 5200 ft/min, but they also are replacing the pistons every couple hundred miles. The ignition timing advance will make up for the speed the piston speed and is generally trying to keep the maximum cylinder pressure at the same crank rotation. For a far better explanation, see the article from TeamIntegra.net below http://www.teamintegra.net/sections...?ArticleID=235 
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To get total distance a piston travels in one minute, divide my numbers by six (divide by 12 to go from inches to feet, then multiply be two to account for both the up and down strokes). 
I'm looking at the corolla and the difference between 4th and 5th gears. 4th is 0.89 and 5th is 0.73. If we added a 6th gear with the same percent change, it would be 0.60. With this extra gear, the 70 mph rpms would drop from 2,767 to 2,271. rpm x stroke number would be 8,177 (or to get the average feet per minute number that mrmad mentioned 1,363 ft/min).
Why can't we get this in regular cars!!!???:mad: By the way, just out of curiosity, does anyone know the ideal average piston velocity in feet per minute, since that's apparently the standard unit used, at which a gasoline engine makes maximum torque? That would help determine how far off the manufacturers are when they gear cars for typical highway cruising speeds 
I'm really surprised the regular civic is nearly at 3000rpm at 70mph.
The Civic hybrid has a 1.3 liter engine. The Insight has a 1.0 The Corolla has at least a 1.8. The regular Civic I believe has ballooned to 1.8 as well 
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Civic hybrid: 1,028 ft/min '06 insight: 1,282 ft/min regular civic: 1,690 ft/min corolla: 1,660 ft/min So again, the hybrid engines are designed to opperate at the optimal rpm for fuel efficiency, while all other cars are designed with entirely different priorities. By the way, I chose 70 mph as a good compromise between the more optimal highway speed for FE of 5560 mph and the typical speeds seen on highways these days of 7580 mph. It also happens to be the speed I'd like to be able to drive and not take a huge FE hit. Interestingly, my Duramax diesel truck has a piston speed of 1,098 ft/min at 70 mph, so evidently the diesel trucks get more FE consideration than the so called economy cars :confused: 
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Efficiency of an Otto engine is typically demonstrated in terms of compression ratio whereas the diesel cycle is in terms of the cut off ratio... It is very likely that it's not so much an FE consideration, and more of a general diesel design consideration... 
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