So what if the camera loses sharpness after f11? For pixel peeping purposes or what is the correct term? Only then the sharpness loss will be that much visible.
For me its better to have a good/great shot than to be 100% technically correct. Since I've realized that, ISO1600+ isn't that "scary" anymore. Of course depends what you shot. I don't like even ISO800 when shooting stills with cars/people, but life/concert photo, that's another story.
And I agree with the "need" to purchase ND filters, so you don't have to resort to high f-stops, but until I buy one, f22 wont kill me
P.S. Sorry if the tone of the message may sound a little harsh, but it's not.
@Willd - I'll read that article as soon as I can, sounds interesting and photos are very good on first glance.
I photograph drift like that and can get very nice, constant, results. Are you using central auto-focus point or some sort of AI within the camera (3D Matrix metering for Nikon, I'm sure that Canon has something similar, but don't know the name for it).