How to change Google Chrome's default fallback Favicon

When you visit google.com you see its favicon:
An icon you easily associate with Google.

But now why do I also get Google's favicon on pages with no favicon? It seems to work like a fallback favicon. This way, having lots of tabs opened (with lots of Google's icon), it's always hard for me to find that one tab that has my Google search results.
So is there any way to change this fallback icon so I don't get tabs like ?

Chrome Version: 18.0.1025.163
Mac OS X Lion 10.7.3

I think it's a bug, not a feature. I revisited the page from the screenshot and now I get a globe icon. So I thought "wow, it must have been fixed by Google already," but just to be sure, I typed some random words into Google (like f.e. tiger and feiertag) and opened about 15 search results each in a new tab. The last two tabs had the Google icon again: (this and that).

When I added a new tab and copy/pasted the same URL from the "broken icon tab" the icon was a globe again. So I guess there's nothing you guys can do, we'll have to wait for Google to fix it. At least we know it's a bug now...

This indeed looks like a bug. Check your installed extensions (if any) in Chrome. There might be one related to favicons, that causes this problem. If in doubt, temporarily disable all extensions. Also try to clear the cache (and if this does not help also history).