Item Elevators

Some item elevators

The Good
- Input can be any of the droppers
- output is the topmost dropper
- It's silent
- infinitly stackable, where infinite < 256 ;)
- you can arrange the redstone in a line, or in an L-shape
- you can exchange the redstone/comparator-repeater parts, so that either is on front and the other on the back, on either side.
- it does not keep an item in a dropper.
The Bad
- It can clog
The Ugly
- input and output can be on one side only

I did not design these (well, I might have modified them, but the initial concept is not from me), but I wanted them somewhere so I can refer other people to them.