Wishlist: Domain Slider

This may have been discussed before (so I apologize if I missed an earlier thread)... but I've been thinking that a domain slider could be very useful as an input control.  It would function very similarly to a regular number slider, but it would have two control handles.  The output would simply be a domain (or Interval) so you would only need a single output (not two outputs for the start and end of the domain).  It could be nice to have a draggable handle between the two points allowing you to move both points simultaneously... or simply move each point separately.  Would this be beneficial (or easy to implement)?