That is an idiotic statement. It has nothing to do with new and old technology. You have the 40D with an APS sensor and a 1Ds with a full frame CMOS sensor that is 1.6X larger with approximately the same number of pixels. The pixels on the 1Ds sensor are LARGER. This is just common sense.
Are you sure the "pixels" on the 1Ds are larger? One would assume so, but the term pixel pitch has nothing to do with the size of the pixels on the chip, but the spacing of the pixels. I have never been able to find any reference by any camera maker on how large the sensor sites themselves are.
One of the main improvements in chip technology has been to decrease the "empty" space between pixels, making the pixels themselves larger. While the 40d has a smaller pixel pitch than the 30d, the reduction in size wasn't proportionate to the spacing because more space was eliminated between sites. In addition, improvements in micro lens technology means the each pixel of the 40d gathers the same amount of light (signal) as those on the 30d (according to Canon).
Of course the other part of the equation is the noise, and this is where most of the improvements have come in sensor technology. Each sensor site of the 40d features a much smaller and improved A/D converter, resulting in far less noise. As the gain is turned up on the sensor to achieve higher ISO, the noise does not scale as rapidly as that of the 1Ds.
So while each pixel of the 40d may not be able to gather as much physical light as a pixel on the 1Ds sensor (kind of the "bucket" thing from your links), the ratio of signal to noise is better, especially as you increase ISO.
I have owned and used extensively a 1Ds, a 1Ds MarkII, and a 5D. I have had a 40d from Canon since the middle of August, and I believe the 40d is nearly the equal of the 5d when it comes to noise performance - a camera which out performs the 1Ds in noise by a significant amount. The 1Ds relative to today's standards doesn't perform that well when it comes to noise.
DPreview data shows Luminance noise of the 40d at ISO 3200 is actually slightly better than than the 1Ds at ISO 1250. (graphs located here
(1Ds) [a href=\"http://www.dpreview.com/reviews/canoneos1ds/page14.asp]http://www.dpreview.com/reviews/canoneos1ds/page14.asp[/url]
Perhaps the original poster doesn't need ISO above 200, so it doesn't matter. Don't know.