I have put together a preliminary patch against GTK which allows you to set the position of scrollbars to something other than the default right, bottom.

This is particularly useful if you are left-handed and use a tablet, or tablet PC. Imaging scrolling down a long webpage with your left (pen) hand leaning over to the right-hand scrollbar: you obscure what you are reading with your own hand.

The patch is described on my left-handed page, and is available both there and on the relevant GTK bug page.