Whoa, never thought Chroma filter would work for the scrollbars as well... A long time ago, when I did use to create html pages using pure notepad, the day I saw the scrollbar coloring trick was memorable, since I've always been more into graphics than anything else, and from then on they could be stylize from that awful-looking gray bar. But I never ever thought of combining these two at same time... Was this your discovery?
One can accomplish neat visual effects by using that, like showing just arrows and the scrolling bar itself. I suppose this trick works in non-framed pages as well, right? Also, does this works fine with background images (fixed or not)?
(consider the following only in case this works fine in non-framed pages as well)
I think you could have named this just 'Transparent Scrollbars on IE' or something similar, since this tutorial is pretty useful to any page viewed in IE, independently of frames or not. The way it is named and structured right now may make this article be overlooked by many people who simply don't use or link iframes or even frames (and imagine that there are a lot of people who hate them, like me =p). All this is just a suggestion to maybe bring more people to the topic, don't get me wrong, ok?