Well, i some websites with frontpage( i know) and i could always make my own scrollbars wit a little script.....In those days i had IE and it worked now I have firefox and they still work so..you must only ask for opera and netscape users but i think that those have no problems with custom scrollbars
The script i will search and post here!!
This is one of the scripts, but this one only works in IE....
<STYLE type="text/css">
BODY {scrollbar-3dlight-color:#00FFFF;
scrollbar-arrow-color:#7FFF00;
scrollbar-base-color:#FFF8DC;
scrollbar-track-color:#556B2F;
scrollbar-darkshadow-color:#FFF8DC;
scrollbar-face-color:#DC143C;
scrollbar-highlight-color:#8B008B;
scrollbar-shadow-color:#7FFFD4}
</STYLE>
You should change the colors behind the :#things to change the color of the scrollbar.