Glass hoppers, glass comperators, glass repeaters

There should be a new block called glass hopper, which would be created by using a hopper and a glass block. It would behave exactly like a hopper except it would be full block. This would make a perfect top-layer block for the item elevators in the nether. Right now tuning the exact exit point of items from the item elevator is a bit cumbersome. But placing these blocks as the top layer of item elevator will make items to pass through these blocks and to get sucked by them immediately, which would enable more flexible design in terms of the height of the item elevator and the placement of the dropper at the bottom. Similarly having glass comperators and glass repeaters can enable vertical stacking of these blocks, which would make certain circuits more compact. Or a restone torch can be placed at the exit side of these blocks for more compact inverters.