Ok so I updated to minecraft 1.5.2 and went to my test world. Unfortunately all of my item sorting devices have failed, so I checked that out.
I do not know if this is a bug but, when there is redstone signal next to the hoper like so
[ ]=Block(any except translucent)
_ = redstone signal (on)
This no longer will stop the hopper from outputting items into the next! One thing to note is that it transport items twice as fast! If you add a lot of items (like a stack), it will travel in two, not one by one. I have tried to put a torch next to the hopper like so.
Items can still pass through, but I realized that items now go at the normal one by one pace.
The last thing I tried is this:
[ ] \/
This had finally worked. I don't know if this is a bug or something but something needs to happen. This pretty much broke all of my item sorting and item payment devices (about 7).
EDIT: This only happens when you put hoppers like this, not with chests