What about having the contents automatically resize the dock length according to the amount of Icons? Then you won't have all that extra space making it look stupid. Then also, if there becomes too many icons, you can specify, say after 10 icons, either create a new row or put in the left/right buttons...
what would be sweet is that if there's too many icons to be displayed and you need a left and right button... why not make it so that when you hover over towards the left the icons automatically move to the right (and same in reverse)... kind of like in Flash with scrollable thumbnails across the bottom... it would save a few clicks...