Power Meter

A power meter item that behaves like a comparator but rather than outputting a power signal it would display the power level from 0 to 15.  This could be a numeric display like an alarm clock or it could be a bar grid with a red stone light level system that just got filled from 0 - 100% or 0 -15 bars. 

This "power meter" item would be placed exactly like an item frame (all sides of a block) and measure the power of the block/item it was placed on.

I would love to use something like this in my hopper sorting system to measure how full a chest is so that the circuits don't cause overflow when the chest gets full.  I would place it on the double chest and it would measure the contents just like the comparator does.