CSS scroll-thumb/bar colour attributes work fine in IE 5 and 5.5.

Was there a special option you had to enable? I never saw a coloured scroll-bar until I installed IE6.

Changing the width of a scroll bar would be a BIG faux pas.

I'd be tempted to say that about changing the colour, too; my first impression on a page that's done this is always "Why isn't there a scroll-bar?"

Peter