Plan 9 Style Scroll Bars

[Victor Nazarov <vir comtv ru>]

Are there any gtk themes with scrollbars that operate just like plan9 
scrollbars?

I. e. left click on scrollbar moves up, right click moves down. Step of 
scrolling depends on the position of cursor on the scrollbar. High 
position is little step, more accurate scrolling, low position meens 
faster and less accurate scrolling. Holding down left or right button on 
the scrollbar meens scrolling with constant speed, down or up 
respectively. The position and visible range is shown, just like it is 
now in most/all themes.

Are there any and how difficult is it to implement such a behaviour for 
gtk2?

--
Victor Nazarov