The generalized statements about the gaps being too small causing insufficient burn and too wide having a weak spark are spot on. As you widen the gap, you need to increase voltage to cover the gap. Also, as you increase pressure at the top of the compression cycle, you'll need to either increase the voltage output to the spark plug and/or reduce the gap of the spark plug. If you don't, the spark will not jump the gap as efficiently and therefor you won't get the best performance out of your vehicle.
I don't know if this will exactly answer your question, but is about the best I've found thus far (if I find more, I'll add to it), but it makes a lot of sense to me:
As a rule, a properly gapped spark plug will burn hot without being too wide at high rpm to cause a misfire. Ironically, the car manufacturer's recommended spark plug gap is not optimal! The recommended spark plug gap is designed to be adequate for cold starting and smooth driving on a car that is in need of an engine tune up. If you drive your car normally and tune the engine regularly, you can increase the spark plug gap by about 0.010" for better performance and better fuel economy. However, if you drive at full throttle most of the time, you should reduce the gap by about 0.010" for better performance. The spark plug itself, and the residue that forms on it, would indicate whether the gap is too big or too small. A light brownish discoloration of the tip of to porcelain insulator indicates the proper operation of the spark plugs with the gap being ideal or close to ideal for the most recent engine speeds. Thus, to check the spark plug gap at high engine speeds, you'd need to run at full throttle and immediately turn the ignition off without allowing the engine to idle. But ultimately, you'd need to run your car on a dynamometer to find the best spark plug gap, and the right ignition timing for your engine.
There is a lot more information on the page which gives indication about how the gap affects things, so it's worth a read in my book.
I would say, though, the ultimate gap range for one vehicle is going to be different than it will be for another. As is stated at the end of the excerpt, you'd need to run your car on a dynamometer to find the best spark plug gap. Any given car is going to be different. Some manufacturers may have the optimal gap set, while others will be a lot more conservative.
All-in-all, I've not found any empirical data which shows exactly what the difference is between gaps on any given vehicle, but as I've stated, every vehicle line is going to be different anyway. This makes it hard to come to a strict conclusion.