I agree that going over recommended voltage is overclocking. But what is the standard? Are we talking about the industry standard? IEEE? JEDEC? Look at all the DDR3's that require more than 1.65V - they break Intel's standard. Clearly, the current industry standard for 1066 modules is voltage over 1.9V - not a good thing in my opinion.
A quick check of DDR2 800 at NewEgg shows 170 modules. Only 63 are 1.8V - the "standard" for DDR2 800. So are all the others overclocked 667s? No, they're 800s that want more voltage. When you move to 1066 you find 54 modules - only 6 of them at 1.8V. Are these 6 really 800 modules - no, they're better designed modules that deliver 1066 at lower voltage. Some of the others, especially those wanting over 2.1V are no doubt 800s that are being pushed to 1066 by more voltage - but they still have 1066 SPDs. Not just a new stuck-on label.
I've used 3 different 1066 modules in my system so far. The first wanted 2.2V to run in 1066 mode - I couldn't do that. These were lousy RAM that needed high voltage to achieve 1066 mode - likely 800s being pushed too hard. But they still are 1066 modules because I've seen the SPD for them and they list that mode. (OCZ Platinum)
The 2nd only use 1.8V and come up automatically in POST as 1066, with no changes to timing, freq or voltage. They are without a doubt, REAL 1066 modules. Unfortunately, they had lousy timings and I returned them. (Crucial/Micron)
The 3rd come up as 800s until I set the freq to 1066, then come up as those. Again, real 1066 modules. (G.Skill Pi)
The 1st modules were made by OCZ. OCZ now makes a 1.8V version of their 1066 modules to avoid these problems. Again, real 1066 modules. (Also OCZ Plat but not widely available)
Let's agree that some modules sold as 1066 are "factory-altered" 800s - using higher voltage to perform at 1066s. But to say that 1066 modules really don't exist is false - they do and it's not just a marketing scam. Companies are putting out real 1066 RAM and I think we'll see much more of it in the near future as they get tired of people returning their "fake" 2.2V modules.